Asian elephant
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Asian elephant ( Elephas maximus ) |
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| Elephas maximus | ||||||||||||
| Linnaeus , 1758 |
The Asian elephant ( Elephas maximus ) is a species from the elephant family and is the second largest land animal on earth after the African elephant . Like its African cousin, it is distinguished by its trunk , tusks , columnar legs, and general height. Both differ in the size of the ears, the slightly different back line and in numerous individual anatomical features. The range of the Asian elephant includes South Asia , Southeast Asia including parts of the Malay Islands and southern East Asia . The former occurrence was much larger. The animals inhabit various forest landscapes and open land areas from sea level to higher mountain areas.
The way of life of the Asian elephant has been well researched through numerous studies, but has not yet been worked out in as much detail as that of the African elephant. The social structure shows a complex structure. The closest connections exist between mother and young animals. Several of these groups form a herd or family association of related animals. The individual animals often form short-term partnerships, which, however, have a stable character due to repeated reunions. The hierarchy within the family group is rather flat, a dominant lead cow like the African elephant plays a subordinate role. The individual herds use action spaces, the size of which depends on the respective landscape conditions and the food resources. The communication with each other takes place in different ways, for example with sounds in the low frequency range , with numerous chemical signal transmitters and through contact mainly with the trunk. Similar to the African elephant, the Asian elephant also has high cognitive abilities, including self-awareness.
The diet includes soft and hard vegetable foods with regional and seasonal variations. Harder plant foods predominate in the rainy season, softer ones in the dry season. The size of the animals means that an individual invests the majority of his daily activity in food intake. Reproduction mostly takes place all year round, but it can also be limited in more seasonal landscape areas. The musth that occurs annually is characteristic of bulls , which is associated with increased aggressiveness. Rival fights can occur during this phase. Cows have a long rutting cycle that is untypical for mammals. As a rule, after a gestation period of around two years, a calf is born that grows up in the maternal group. For the duration of the rearing period, the cow stops rutting. The female offspring remains in the family group, the male leaves it and goes his own way.
The Asian elephant has made a strong cultural impact on human history. The taming may go back to the third millennium BC. The animals were used, among other things, for construction work, in military service or for representative purposes. With wild elephants, however, there are numerous human-animal conflicts every year. The first scientific description dates back to 1758. In the course of time, several subspecies were introduced, but from a genetic point of view they do not exist. Rather, two genetically separate groups can be distinguished, both sharing almost the entire range. Early fossil records of the Asian elephant date back to the Middle and Upper Pleistocene , but are generally rare. The population of the species is considered to be endangered and is in decline, primarily due to landscape destruction and poaching.
features
Habitus
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After the African elephant ( Loxodonta africana ), the Asian elephant is the second largest land mammal on earth today. Like its African relative, the animals can be recognized by their proboscis , tusks and columnar legs. The head-trunk length is about 550 to 640 cm, plus a 120 to 150 cm long tail. Male individuals with an average shoulder height of 270 cm and a maximum of 340 cm and a weight of around 3600 kg and a maximum of 6000 kg are significantly larger than females. The average shoulder height is 240 cm (maximum over 250 cm) and the average weight is 2720 kg (maximum 4160 kg). Most of the analyzes of Asian elephant sizes come from animals native to India, but they tend to be larger than populations further east. From the 1940s, there is information on individual individuals with heights between 323 and 343 cm (the latter value relates to a skeleton). The Asian elephant from the island of Borneo , on the other hand, is about half a meter smaller on average. In contrast to the African elephant, the back of the Asian elephant is arched or straight, the highest point of the body is on the top of the head and not on the shoulder. The head is compressed, two prominent humps rise on the forehead. The tip of the trunk has only one finger-like extension instead of two like the African elephant. In contrast to the latter, the ears are significantly smaller and folded on the upper edge. They are up to 60 cm high and 55 cm wide and cover an area of around 0.5 m² (based on both sides of the ear). The thickness is only around 1.5 cm. Tusks are usually only developed in bulls. The skin mostly has a gray tint, animals in the eastern part of the distribution area often have a lighter basic color than those from the western part. Sometimes individual pigment-free zones appear on the trunk and ears, which then appear flesh-colored. The thickness of the skin varies, averaging 18 mm, but it can be up to 30 mm on the back. Hair is sparsely developed, but thicker than that of the African elephant. Often there are individual tufts of elongated hair, for example on the lips, on the legs and at the end of the tail. The front and rear feet each have five toes. Outwardly visible there are five hoof-like nails on the forefeet and four to five hoof-like nails on the hindfeet.
Skull and dentition features
The Asian elephant's skull is massive. Its length is 86 to 97 cm in animals from India and Sri Lanka, in those from mainland Southeast Asia and Borneo it is on average shorter with 75 to 80 cm. In general, the skull of the Asian elephant is not as inflated as that of its African relatives, but rather more pressed in front and behind and stretched in the occiput. This makes it appear higher overall. When viewed from the front, the forehead line is characterized by two lateral humps and a concave indentation in between. The humps can also hang slightly over the forehead when viewed from the side, so that an overall dented profile is created. The frontal bone is narrower and arched and not broad and flat as in its African cousins. The alveoli of the upper tusks, which are largely formed by the median jawbone , are closer together and directed downwards. This differs from the African elephant with its laterally sloping alveoli. In contrast to this, the nasal opening, i.e. the point of attachment for the trunk, in the Asian elephant lies clearly above the orbit and not on its level. The short nasal bone that starts here is narrower and directed more forward. The greatest width of the skull is reached at the level of the eye window, in the African elephant it is significantly lower. On the occiput , the joint surfaces for the spinal connection are significantly higher and are clearly rounded. The adjoining back of the skull then rises steeply, while in the African elephant it is inclined forward to a certain extent. In relation to the position of the occipital joints, the opening of the auditory canal is lower than in the African elephant. Further differences can be found in the design of the zygomatic arch , the parietal bones or the contact between the middle jaw bone and the upper jaw. A general feature of the elephant skull is the strong formation of air-filled chambers in the forehead area. The honeycomb-like structures penetrate large areas of the frontal, parietal and nasal bones as well as the upper jaw. This leads to an increase in volume of the skull, which makes it lighter overall, but also provides a larger attachment surface for the massive chewing and neck muscles.
The lower jaw is made of solid bone. In the Asian elephant it is short and compressed and appears overall swollen or not as elongated as in the African elephant. Its total length corresponds roughly to the total height of the ascending branch. When viewed from above, it shows a rounded to U-shaped course. In contrast, the lower jaw of the African elephant is V-shaped. The symphysis at the front end, which connects the two halves of the lower jaw, is directed more downward in the Asian elephant, and it is narrower and relatively shorter than in the African forms. On the ascending branch, the crown and articular processes point clearly inward, while in the African elephant they just rise. By compressing the lower jaw, the crown process takes a position approximately in the middle of the lower jaw length. The articular surface for connection with the skull is stretched to the side and not rounded, and also directed forward. On the outside of the ascending branch, the masseteric fossa of the Asian elephant digs deeper than that of the African elephant and is also further expanded.
As with all elephants, the bit is highly specialized. It consists of a total of 26 teeth with the following dental formula : . In the front dentition, only the upper tusks are formed, which represent the hypertrophied second incisors . As a rule, only the bulls of the Asian elephant have tusks, but cows sometimes have small, tusk- like teeth without tooth pulp (so-called tushes ), which are only around 20 cm long and have an oval to rounded cross-section. In the African elephant, on the other hand, both sexes often have tusks. The development of the tusks is quite different in the male animals, since there are occasional individuals without such structures. For example, according to studies in Sri Lanka, only 2 to 7% of bull elephants have visible tusks, but this is attributed to an artificial phenomenon caused by human hunting. The longest known tusk of an Asian elephant measured 302 cm, the heaviest specimen weighed 39 kg. Tooth enamel is mostly only formed at the tip. The tusks of the Asian elephant run more downwards and less laterally than in the African cousin. In the former, they are also clearly straight and only curve in the further course.
The rear dentition consists of three premolars and three molars per half of the jaw. The former are to be understood as the formation of the deciduous dentition, the latter represent the permanent teeth. As in the African elephant, the change of teeth takes place horizontally and not vertically as is usual with most other mammals. A new tooth is continuously pushed out from behind, while the front one is chewed off due to stress and ultimately falls out. In principle, elephants only have one to one and a half teeth per half of their jaws. In the course of its life, the Asiatic elephant changes its teeth five times as a result of this horizontal change of teeth. The exact sequence has not been studied as well as that of the African elephant. The first generation of teeth (dP2) break through the jawbone before birth. It fails around the age of 2. The following teeth dP3 and dp4 are largely chewed off at around 5 to 6 and around 13 years of age. The first permanent molar (M1) fails at around 25 years of age, while the second (M2) is likely to be lost in the mid-30s or a little later. From then on, only the last molar (M3) remains in the mouth. As with all elephants, the molars consist of a series of enamel folds with a lamellar shape. The individual enamel folds have a parallel course and lack the diamond-shaped bulge in the middle, which is typical for African elephants. When the teeth are chewed more, the enamel folds often dissolve into separate loops. Compared to the African forms, the Asian elephant is more modern in terms of tooth structure. It has higher ( hypsodontic ) tooth crowns and a higher number of enamel folds, the number of which increases from the first to the last tooth. There are an average of four to six folds on the anterior premolar, and the number on the last molar varies between 20 and 29. The lower teeth usually have more enamel folds than the upper ones. The lamella frequency (number of lamellae on 10 cm tooth length) is 5 to 9 and is significantly higher than that of the African elephant. The dense layer of enamel folds means that the respective tooth enamel thickness is relatively small at 2.5 to 3.0 mm. The weight of the individual teeth varies considerably. The last molar can weigh up to 5.2 kg, while the front premolar only weighs around 9.0 g.
Distribution and habitat
The range of wild Asian elephants today includes the southern , south-eastern and southernmost areas of eastern Asia . The species is native to around a dozen countries. The occurrence extends from India , Nepal and Bhutan in the west via Sri Lanka , Bangladesh , Myanmar , Thailand and Cambodia to Laos , Vietnam and China in the east and Malaysia or Indonesia in the south. Depending on the source, the total size of the distribution is given as around 487,000 to 879,000 km², but it can also be smaller. Originally, the Asian elephant was widespread from West Asia to East Asia and inhabited an area of around 9 million square kilometers. The western population , which reached as far as Syria , probably died as early as the 8th to 9th centuries BC. Chr. From. The eastern one probably died out during the Song and Ming dynasties between the 12th and 17th centuries.
In India, the Asian elephant was once found in large parts of the subcontinent. Today its occurrence is essentially limited to four regions:
- In the north-west there are scattered stocks in the foothills of the Himalayas of Uttaranchal and Uttar Pradesh , some herds of which also migrate to Nepal;
- In the northeast, the distribution extends from the eastern border of Nepal in the north of West Bengal via Assam along the foothills of the Himalayas to the eastern Arunachal Pradesh and Nagaland ; further west to the mountainous regions of Meghalaya and to the plains of Brahmaputra ;
- In the central part of the country, extremely fragmented populations have been documented on the Chota-Nagpur plateau in Orissa and Jharkhand , and since the mid-1980s in the southern part of West Bengal and Andhra Pradesh ;
- In the south, individual populations live scattered in the valleys of the western and eastern Ghats in Karnataka , Kerala , Tamil Nadu and Andhra Pradesh ;
India is home to the largest wild population of the Asian elephant within any country's borders, with an estimated 26,000 to 28,000 animals. Around half of them live in the southern part of the country, another third in the northeast. The rest is distributed over the other two regions, a very small group of around 40 animals is native to the Andamans .
In the bordering countries in Bangladesh and Bhutan, the Asian elephant can mostly be found in the border area with India. As a rule, the animals use areas that are not very attractive for humans. The Nepalese stocks are also largely found near the border in the lowlands. The animals, which were once widely distributed over Sri Lanka, are only found in the drier east in the deeper parts of the country. Also in southeast Asia there are usually dispersed populations, whereby the species is still quite widespread in Laos, while in Cambodia and Vietnam it predominantly inhabits the southern areas. Larger stocks in Thailand and Myanmar have been observed in the border area of the two countries, in the former also on the Malay Peninsula , where there are even larger forest areas. From here, the Asian elephant then appears in the interior of Malaysia. In the Malay Archipelago , it is only found on Borneo and Sumatra , the two largest Sunda islands . The stocks are, however, very fragmented. In China, the species is limited to the southernmost areas of Yunnan Province , such as the Xishuangbanna Autonomous District and the neighboring city of Pu'er to the north . In contrast to India, only a few studies are available on the individual populations.
The Asian elephant is a generalist that uses a wide variety of landscapes from open grasslands to evergreen tropical rainforests , deciduous forests and secondary forests to scrubland and cultivated areas. Its current distribution is largely a result of the dense human settlement in the distribution area. In regions with a low human population density, the Asian elephant mainly uses transition zones from closed forests to open grasslands or grass-dominated habitats . In Sri Lanka, for example, he prefers savanna-like areas over forests. The altitude distribution ranges from sea level to around 3000 m, at higher altitudes the animals can be found in the eastern part of the Himalayas, especially in summer. Little information is available on population density. For the Bardia National Park in Nepal, it was determined to be 0.5 individuals per square kilometer in the dry season. A comparably large area in the Biligiri Rangaswamy Temple Tiger Reserve in southern India bears 1.7 individuals. Investigations in the years 2005 to 2009 in the Udawalawe National Park in Sri Lanka revealed an intact population of the Asian elephant consisting of 800 to 1160 individuals. It was made up of around 240 bulls and almost 290 cows, the rest was made up of calves and young animals. The ratio of male to female animals was 0.84: 1, on average there were about 102 to 116 cows per 100 km².
Way of life
Territorial behavior
General and activities
In contrast to the African elephant , the Asian elephant's way of life is less well researched in many respects. The animals are crepuscular and diurnal . According to animal examinations in Sri Lanka, the basic daytime activities take place in the morning between 08:00 and 10:00 and in the late afternoon between 16:00 and 18:00. There are slight differences between male animals and the family groups with earlier onset of activity in the former. Shifts can be observed particularly in regions with greater human influence. The animals mostly rest during the heat of the day. Certain activities also take place at night, but their intensity is significantly less than in daylight. The main activity of the Asian elephant is foraging, which takes up most of the available time budget. Other common activities include walking, scouting out unfamiliar objects, and standing. There are also a number of other activities that play a rather subordinate role, such as playing, wagging your tail or ears, various baths in water, mud or dust and the like. The Asian elephant defecates about every hour and a half , which results in a frequency of 18 to 20 times a day. The daily sleep duration is relatively short and is around 4.6 hours with slight differences between the seasons. Most rest periods begin shortly after midnight. Usually an animal sleeps standing. A lying position is only rarely taken, an animal spends around an hour in this. Exceptions are calves that sleep and rest longer on average than adult animals and usually lie with them. A standing position is common from around the age of nine.
The body temperature of the Asian elephant is around 36 ° C. It varies between 35.7 and 36.8 ° C during the day. The changes run parallel to the daily rhythm with the lowest body temperature in the late night and the highest in the late day. As the Asian elephant cannot sweat or pant, its heat dissipation options are limited. Lowering the body temperature during the cooler night may create a temperature buffer for the next day. In principle, this behavior is similar to some heterothermal, desert-dwelling ungulates . Another way to regulate body temperature is by evaporation of water on the body surface. A function of the wagging ears - as is often assumed - is probably not there.
Social structure and use of space
The Asian elephant has a complex social structure, generally there is no territoriality. The closest connection arises between the mother and the young. Several of these connections form a family group or flock. The size of a herd increases with the number of childbearing generations. According to studies in Sri Lanka, such family groups consist of 2 to 28 individuals, but more than half of the groups are smaller and include 6 or fewer animals. Two herds observed in the Western Ghats in southern India consisted of 8 and 19 individuals, respectively. The larger of the two included 11 adult female individuals and 4 calves and young animals each, the smaller one combined 4 cows and 2 calves and 2 young animals each, plus a single bull. The individuals from a family association are related to each other, which is indicated by the same haplotypes . Genetic tests indicate little maternal exchange between the individual herds. It is generally assumed that the family association of the Asian elephant is more loosely structured than that of the African elephant. Perhaps it is more similar to that of the forest elephant ( Loxodonta cyclotis ), whose wooded habitat is more similar to that of the Asian elephant due to the cheaper food available than compared to the seasonally influenced savanna landscapes that the African elephant inhabits. This is confirmed by long-term studies in the Udawalawe National Park in Sri Lanka. It was found here that predominantly group sizes with 3 individuals appear who belong to a loose family group of around a dozen or more animals. The respective composition of the small group varies and can change within a day, so it is not linked to external factors. The studies also showed certain individual preferences in group formation, whereby each cow forms a temporary community with more or less clearly defined other individuals. The individual groups may only exist for a short time, but they are constantly re-forming over certain time intervals and can therefore be viewed as stable in the long term. As a result of this constant formation of new groups, each individual is strongly socialized within the genetically related family group. The formation and breaking up of the small groups is similar to the “fission-fusion” social structure (“separating and coming together”) of the African elephant. In contrast to this, in which whole family groups often join together to form clans in the seasonal rhythm, this takes place on a lower level with the Asian elephant. As a direct consequence of this, the social hierarchy of the Asian elephant is rather flat and a matriarch like that of the African elephant, i.e. the oldest and most experienced cow leading the herd, plays a much smaller role. The linear ranking typical for the herds of the African elephant, in which one of the oldest daughters takes the lead after the death of the lead cow, is also less pronounced in the Asian elephant for these reasons. Sometimes larger herds are formed in the Asian elephant, but this happens far less often.
The social structure of the bulls is much less well studied. As a rule, they live alone or, if they are still relatively young, in their own associations. However, these associations are largely unstable and an internal hierarchy is unknown. To mate, they join a herd and can spend several months in the company of the cows. Since mating is not seasonal, at least one bull can be found in around 40% of the herds at any time. The bulls are rarely aggressive towards each other, so there is occasionally more than one bull in a herd. Exceptions, however, are phases in which cows come into the rut .
The individual family groups and bulls use activity areas of different sizes depending on the region . The respective extent depends on the availability of food resources and water as well as the habitat . In areas more heavily populated by people, the fragmentation and influence of the landscape play a major role. Most of the time, the action spaces include different types of landscape that are used in an annual cycle. The hikes undertaken are in most cases limited to the respective action area, so that the Asian elephant is sometimes quite true to location. This also means that individual animals or family groups, for example, do not find better food sources outside their respective territories. In several investigations in fragmented forest areas in the Western Ghats of southern India, the respective action areas of different herds comprised between 105 and 350 km² with a considerable spatial overlap. The respective size of the action area varied significantly depending on the season, and the herds also used different core zones of around 35 to 50 km² in size. As a rule, during the day the animals were mostly in natural rain or alluvial forest areas, at night they preferred landscapes near rivers or water, but avoided swamps and, above all, human settlements. The family groups only occasionally carried out their activities on the adjacent plantations. In an overarching annual rhythm, the animals gathered in short grass landscapes in river valleys in a narrow area during the dry season, but then spread over larger areas in the rainy season and penetrated landscapes with longer grasses. In central India, varying sizes could be determined for the areas of activity of the Asian elephant, they amounted to 259 to 4349 km². The strongly differing sizes resulted from the fact that some individuals undertook considerably more extensive annual migrations, which took place mainly in the rainy season and sometimes linearly over distances of up to 250 km, while others remained in their ancestral region. The areas actually used during the season were in all cases significantly smaller and narrowed to 35 to 55 km². Animals in south-eastern Sri Lanka, on the other hand, move within 41 to 459 km² action areas, the actual core areas make up around a quarter of this area. Here, too, there is a clear overlap between the areas. In contrast to the populations of the Indian subcontinent, however, no major annual migrations have been found so far. Little information is available on the populations of Southeast Asia. A study from the 1970s determined the size of the action areas on the Malay Peninsula at 59 to 167 km². A cow equipped with a radio transmitter moved in the 1990s in Taman Negara in Malaysia over an area of around 6800 km². Since the animal had recently been relocated, its migrations turned out to be more orientational than using an actual action area. Later, the movements were restricted to areas of 350 and 9 km², respectively. In contrast, the action area of a bull observed at the same time in the same protected area was around 340 km². Again a young bull from Kelantan , also Malaysia, had developed an area of around 9.5 km² within four months in 2011, although the area actually used was smaller. The distance covered was 88 km. For animals on Borneo, an expansion of the action areas of 250 to 400 km² in undisturbed forests and around 600 km² in fragmented landscapes was determined. The core areas were significantly smaller. On average, the herds covered around 1.1 to 1.8 km per day, and one group covered around 200 km in around four months. In the event of human interference, the daily distance covered could increase up to 9.5 km. Most of the elephants on Borneo use forests around 300 m above sea level.
Agonistic behavior and communication
The meeting of two individuals can take place in different ways. If an individual perceives another, it usually lifts its trunk with the tip of the trunk towards the other person and turns the body. Depending on the situation, the ears are also raised, the head remains in a normal position or is slightly raised. Contact is made by touching with the trunk, often in the face area on the ears, eyes, mouth and temporal glands, but also on the tail, in the genital area or on the feet, sometimes the contact also includes the introduction of the trunk into the mouth of the other animal. The following further intensity often depends on the extent to which individual individuals know each other or are strangers to each other. In the former case, this leads to marginal to tolerant behavior in same-sex animals. In the latter, playful fights or "pseudo-fights" can occur, which usually prevail among younger bulls. In direct confrontation at distances of 5 to 10 m, the head is raised slightly, the ears spread and the trunk is swung back and forth. The subsequent attack usually ends in a push and pull competition with trunks looped around one another. If none of the opponents can gain the upper hand, the process is sometimes repeated several times. In the case of breeding bulls, however, the fighting is more aggressive. Initial contacts between individuals of different sexes, for example when a bull encounters a family group, are structured similarly. In the following the older cows often ignore the bull, in rare cases they try to drive him away.
The communication of the Asian elephant takes place on different levels and consists of tactile , visual , olfactory and acoustic signals. Above all in tactile communication, the trunk plays a central role, as it not only passes on information, but also receives it from other individuals. The extensive repertoire of chemical communication includes, for example, the distinction between sexually active and inactive individuals. This takes place between male and female animals as well as among their peers. Important signal carriers here are pheromones . For example, certain pheromones of female animals trigger a flehmen- like behavior in male individuals during pre-heat . The active ingredient for this is looplure ((Z) 7-dodecenyl acetate, chemical formula C 14 H 26 O 2 ), which is also found as a sex pheromone in some insects such as butterflies . Another pheromone in bulls, called frontalin (1,5-dimethyl-6,8-dioxabicyclo (3.2.1) octane, chemical formula C 8 H 14 O 2 ), is emitted via the temporal gland and leads to a strong pheromone in cows in heat Mating behavior, on the other hand, produces only slight reactions in other female individuals or other males. The scent trace is recorded olfactorily or tactilely with the tip of the trunk, the "finger" of which is equipped with numerous vibrissae with the most varied of functions and mechanoreceptors . Chemical signals are not only used to recognize conspecifics, the Asian elephant is also able to differentiate between well-known and foreign individuals in alien organisms - such as humans. Experiments also show that the animals are trained for certain odor traces and can retain this knowledge for several months. When you stamp your feet, seismic waves are created that move underground and generate measurable deflections even at a distance of 32 km. Some researchers believe that the very large ossicles of the Asian elephant enable them to receive seismic signals, which in turn would benefit communication over long distances.
The spoken language of the Asian elephant is far less well studied. So far, just over a dozen vocalizations have been recorded. These can be divided into a total of four basic tones, which consist of a trumpet, chirp / squeak, roar and rumble. Each of these basic tones can contain different nuances. Trumpets and roars are often an expression of disturbance, aggression, but also of playing, while chirping / squeaking reflects confusion or disagreement. All three types of sounds occur in the high frequency range between 300 and 6150 Hz . Most diverse are the different resentment sounds, which sound in a low frequency range of 10 to 173 Hz and are mainly used in social contact, either within a herd or between different herds. They also serve to gather together the individual group members who may be further scattered and come from distances of over 100 m. This also happens if the caller is covered by vegetation. The rumble usually induces individuals to respond, creating a kind of chorus in which individual voices are difficult to distinguish. It can be perceived at distances of up to around 500 m. With the help of the resentment sounds in the infrasound range, a group can be coordinated over great distances. The sounds are accompanied by a slightly raised head, flapping ears and an open mouth. The sounds are emitted by almost all group members, with the exception of boys under two years of age. Occasionally there are also combinations of rumbling and chirping or roaring, the function of which is not entirely clear. Social rumbling is by far the most common form of communication within a family group and reaches over 60% of all calls out. By contrast, cops use social rumbling far less often. Similar to the African elephant, the Asian elephant uses two different types of resentment sounds, which are generated nasally and orally . Both types of resentment are arguably used in different situations. Male animals in the Musth have their own vocalizations in a combination of rumbling and chirping, which also sound very low-frequency at 60 to 250 Hz and sometimes last for several hours. Compared to adult individuals, young animals have a similar repertoire of sounds, which, however, differs structurally. It is mainly used when playing, with trumpets and chirps predominating. Roaring sounds usually have an attention-grabbing function, for example when separating from the mother animal. Like its African relatives, the Asian elephant can also imitate strange sounds, which is a rather rare skill among mammals. The benefit of this lies in the strengthening of the bond within the family group and the recognition or differentiation of individuals belonging to or outside of the group.
Comfort behavior and cognitive skills
For comfort behavior , among other extensive baths at waterholes. Here, the Asian elephant splashes off with water that it has previously sucked into its trunk. Dust and mud baths are also comparable, in which the animals wallow in the substrate or spray their trunks. This can usually be observed after bathing, in many cases it takes place in a synchronized manner in a family group, so that a social function can be assigned to the shared bath. It cannot be said with certainty whether this is also associated with direct thermoregulation of the body. An indication of this is that the baths often take place during the warmest time of the day, but the individual individuals do these with different intensities. The water, dust and mud baths may be directly related to skin care and protection against parasites . This involves rubbing against trees or rocks as well as with the trunk and tail. Occasionally there are also cut marks on trees, caused by the tusks. In Sri Lanka, this was often observed in various Pterocarya and Careya species, from whose incisions a slightly smelling sap escaped.
The cognitive abilities of the Asian elephant have long been the subject of research. As early as the 1950s, test series were started in which an elephant learned up to 20 pairs of patterns and was able to identify them both as a pair and individually. In a further series of experiments, the elephant was able to recognize 13 previously learned pairs of patterns after a year. Even after more than 30 years, the animal still remembered the test, but was no longer able to correctly assign the pattern pairs. Other investigations concerned discrimination tests in the form of “black and white” or “small / large”. Younger animals learned much faster than adults. It is also worth mentioning the ability to count and add as well as the ability to compare different sums with one another. The Asian elephant manages the latter not only through visual inspection, but also with its trunk through its sense of smell. In addition to optical signals, olfactory signals also lead to the decision-making process as to whether further actions are worthwhile in certain situations or not. In 2006 it became known that the Asian elephant is capable of self-awareness. However, only one out of three individuals passed the mirror test ; similar attempts had previously failed. However, the results are consistent with other animal species such as the chimpanzee , in which around half of the animals successfully completed the test. The self-reflection also includes the perception of one's own body, which can sometimes be seen as an obstacle to the fulfillment of individual actions. Sometimes the animals use their proboscis as a compressed air pump in order to bring objects that cannot be reached, such as food, within their reach, for which only a few puffs of air are often sufficient. The manipulation of the environment by air is so far unique among mammals and requires a certain understanding of the physical environment. In addition, there is a certain empathy within the individual family groups for the needs or needs of other individuals, which often arise from external influences, for example through separation from the group or aggressive behavior of a conspecific. Assistance from other individuals can be expressed in different ways, for example physically by touching the harassed animal with the trunk in the mouth or on the genital area or by making sounds such as chirps or trumpets. In general, the cooperation in the herd is relatively high, which among other things includes support for injured members. Two or more individuals can also work together to accomplish a task together. Occasionally, as with the African elephant, it is observed that individual animals grapple with the bones of deceased individuals by touching the skull with their trunk or sniffing.
nutrition
The diet of the Asian elephant is based on both hard and soft plant foods. As a result, the main food consists of grasses , leaves , seeds , fruits and twigs . It can therefore be viewed as a generalized herbivore ( mixed feeder ). The exact composition of the food is regional and seasonal depending on the availability of plants. The proportion of soft plant components such as leaves or fruits often decreases in the rainy season in favor of harder plants such as grasses, which then grow fresh. As a rule, the range of species of the softer plants consumed is more diverse than that of the harder ones. Studies on nutrition are available from various parts of the distribution area. In several studies, the food spectrum in southern India was determined to be a total of 112 or 84 plant species, in the southern Nepalese Chitwan National Park and in the adjacent Parsa game reserve the number is 57 food plants, while in northeast India there are 20 and 36 plant species respectively. The animals in southern China, on the other hand, eat up to 83 different plant species, in north-western Sri Lanka there are 116 food plants. The hard plants that are particularly frequently eaten include mainly sweet grasses . Depending on the region, silver hair grass , lemon grass , bamboo and representatives of the genus Leersia can predominate. Among the most widely consumed grasses nationwide, those of the genera Themeda and Saccharum should be mentioned. Among the highly diverse softer food crops have acacias , figs , bananas , the Kamalabaum which Salbaum and Balsambaum- and laurel family , but also grewia and additionally zizyphus and Albizia a certain importance. In addition to the seasonal variations, there are other differences between the different inhabited landscape types, as the analyzes in southern India highlighted. In open grasslands, grasses dominate the food spectrum, whereas in more wooded habitats , soft plant parts. In mixed landscapes, the relationship between hard and soft plants is more balanced. Over the year, however, grass food clearly outweighs soft vegetable food. In southern Nepal, too, the animals from the various locations sometimes have different preferences. This results, for example, in a more species-rich diet in the Parsa game reserve compared to the immediately adjacent Chitwan National Park. It is also noticeable that, according to the nutritional analyzes in southern China, plants that grow early are consumed more frequently than those that grow late. A noteworthy effect here was a negative correlation between the diversity of the plants recorded and the rising temperatures and rainfall over the year. A certain proportion of cultivated species can be identified among the food plants, which sometimes makes up a quarter of the documented plants. Affected are bananas, coconut , mangoes and fingergrass , among others . In many cases, the Asian elephant gets these from crop yields left behind. Much less is known about the feeding habits of animals in the areas of Southeast Asia with dense vegetation in tropical rainforests ; individual studies are available from the Malay Peninsula and Sumatra. In general, the food composition is similar to that in the more northern areas. However, the Asian elephant tends to eat a less grass-based diet in the rainy season. This is explained by the fewer open grass areas and the higher nutrient content of the soft vegetable diet in the region.
Most of the food is taken in with the proboscis; often only the end of the proboscis is used, which loops around the plant and pulls it out. The flexibility of the trunk allows the animals not only to consume a large amount of food, but also to choose it selectively. The selectivity is evident in the grasses, among other things, as the Asian elephant scans different sections depending on the progress of the plant growth. Initially, the animals only eat the upper parts of the grass, only from a height of around 0.5 m do they tear the entire plant out of the ground, but spurn the root sections. The latter is consumed by the Asian elephant in the advanced rainy season after thorough cleaning of the adhering earth, which is done by shaking the trunk several times. The Asian elephant loosens very short grass stalls beforehand by kicking them with their front feet. Sometimes twigs and branches are held with the feet in order to remove smaller parts. The use of the feet represents an important behavioral difference to the African elephant, in which the tusks are mainly used for such work. The debarking of trees, which is also known from the African elephant, can often be observed regionally, especially in the dry season. In the north-east Indian state of Tripura , the Asian elephant mainly does this on teak and cashew trees ; in southern India, star bushes and Kydia and Careya species are often affected. Differences in the type of landscape could also be noticed here, since the debarking was much more intensive in dry, deciduous forests than in moist forests or in bush landscapes. Debarking may end up with complete kinking of the trees.
An Asian elephant consumes around 150 kg of food per day. For this, he invests 17 to 19 hours of a 24-hour day or 60 to 91% of his available activity budget. An animal thus consumes between 5.5 and 10.5 kg of food per hour. An amount of food ingested with the trunk is about 150 g. It is estimated that an animal brings its trunk to its mouth every two minutes, in rarer cases, for example when eating fruit, up to three times per minute. The most intensive feeding phases take place during the early morning and late evening hours between 6:00 a.m. and 9:00 a.m. and 3:00 p.m. and 5:00 p.m. respectively. In the midday hours with the greatest heat of the day, the activities decrease sharply. The morning and evening feeding phases are more developed in the dry season than in the rainy season. There are also variations depending on the type of landscape, since in wetter regions there is no such clear bimodal division in food intake as in drier habitats. In addition, the Asian elephant visits a water point at least once a day. Just like when eating, the trunk is also used when drinking, in which it is soaked with water and then brought to the mouth. Only young animals were observed slurping up water directly with their mouths. Most of the time, the Asian elephant goes to the same water points. During extended periods of drought and dwindling surface water, it digs for groundwater with its feet in the sandy soil. Furthermore, salt and mineral licks, which are regularly committed by the animals, are of great importance. Exceptions are probably populations that live in regions with a high salt and mineral content in the soil, for example near the coast.
Reproduction
Rut and mating
In general, the Asian elephant can mate all year round. In regions with a stronger seasonal structure, however, reproduction is more clearly seasonally bound, which among other things increases the survival rate of newborns. The sexual cycle of the cows is extremely long at 14 to 16 weeks (an originally assumed duration of the sexual cycle of 18 to 27 days is based on the observed sexual receptiveness of the cows). It is divided into an 8 to 12 week long luteal phase and a 4 to 8 week long follicular phase. The two are separated by a nonluteal phase, during which there is an increased production of luteinizing hormones with a bimodal output every three weeks. Only the second phase also leads to ovulation ; the function of the first phase has not yet been clarified. Due to the long sexual cycle, cows are usually only ready to receive three to four times a year. Outward signs of the rut are hardly noticeable in females. Occasionally an animal leaves the family group or there is increased tail movements or trunk contact of the herd members, predominantly on the sexual organs. An increased flow of mucus from the urogenital area is probably an indication of the beginning of the sexual cycle.
In bulls, the willingness to mate is expressed through the musth . It can be recognized by the generally higher aggressiveness and by a dark colored secretion that emerges from the temporal glands. At the height of the musth, this secretion runs over the face of the male animals past the corners of the mouth. Further signs are found in the restlessness of the animals, in frequent urination and in reduced food consumption. The musth is generally associated with an increase in testosterone levels. The testosterone content of the blood increases from 0.2 to 1.4 ng / ml in the pre-musth phase to 30 to over 65 ng / ml in the full musth phase. At the same time, there is a relative decrease in the androstenedione content . The musth occurs annually in bulls, but it is not synchronized among the individual individuals in contrast to the rutting of male ungulates . This means that male animals are present in the Musth throughout the year. Musth animals are sometimes found more frequently in the wetter than comparatively in the drier seasons. The first signs of musth appear sporadically in males from the age of 14. However, the full expression only takes place between the ages of 20 and 25. The duration varies between a few weeks and up to five months. The high level of aggressiveness of the bulls during the musth is mostly directed against their own mates and enables them to dominate other males outside of this phase. In principle, fights are rare, but they can be carried out vehemently. They then consist of ramming with the head, fencing with the tusks, and wrestling with the trunk. Under certain circumstances, they result in broken tusks or in the death of the opposing individual, but often the fight ends with the flight of the inferior animal. The fights are accompanied by trumpet calls.
Bulls in the Musth go on a hike in search of cows ready to mate and so join various herds in their course, which leads to a considerable expansion of the action area. According to observations in the Nagarahole and Bandipur National Park in southern India, however, young bulls in the Musth spend on average less time with female animals and stay in smaller herds than older bulls in the Musth, which usually stay longer and in larger family groups. In principle, bulls can also mate outside of the musth, but their options are limited by the potential presence of musth animals. In bachelor groups, only the strongest and oldest bull usually reaches the musth, so that social rank also has a certain influence. This coincides with observations in Nagarahole and Bandipur National Park, where older musth bulls tolerate younger non-musth bulls in the presence of a cow. Conversely, however, a young bull in the Musth hardly ever appears in the vicinity of an older bull in the Musth accompanied by a woman. This means that the musth does bring the bulls advantages when mating with cows, but that these usually only become effective with the male animals becoming older.
The encounters between male and female animals ready to mate result in a number of different courses of action. As a rule, they are primarily used to determine gender and receptivity, for which the trunk is mostly used. Body sections that are examined particularly intensively are located on the anus and in the genital region, on the feet and in the face area, in bulls it is mainly the temporal glands. Most likely, the identification takes place via traces of smell, for example from urine. The entire choice of partners within a herd can take three to four weeks. Females often choose larger bulls in the musth as a partner to younger animals with no musth signs. Wearing tusks also seems to play a role. Well-trained tusks do not lead to successful mating at the same time, as musth and body size play a more important role in the bulls' struggle for dominance. A negative attitude on the part of the courted cow expresses this through vocalizations. The immediate mating game includes wrestling matches with the trunk, neck bites and attempts to climb. They are partially interrupted while the animals break branches or trees, spray their bodies with mud or dust, and sporadically ingest food. The cow behaves passively during copulation . Sitting on the bull often takes no more than 30 seconds, during which time he inserts his penis into the vagina several times for up to 8 seconds . This is done several times within a few minutes.
Birth and Individual Development
The gestation period lasts an average of 640 days (around 22 months). According to observations on 18 pregnant cows in the Pinnawela Elephant Orphanage in Sri Lanka, the birth took place an average of 667 days after fertilization. Typically, a single calf is born that weighs between 80 and 110 kg at birth and is 75 to 90 cm tall. Differences between male and female calves are not known, in the Pinnawela Elephant Orphanage the birth weight for both sexes was around 83 kg, the birth height varied between 87 and 88 cm. Newborns have a thick, brown coat of hair. You can stand and walk within an hour of giving birth, and suckling milk for the first time after a good three hours. A youngster does not necessarily only get milk from its mother, but also from other cows in the herd. The mouth and not the trunk is used for sucking. In the period after the birth, the entire herd takes care of the calf intensively and integrates it into the family group. The distance between the calf and the other group members is very short and is often only around 5 m. The calf spends about half of the time resting, often during the dark part of the day, and another quarter feeding. After six months it begins to eat grass and leaves on its own, but occasionally continues to suckle into the second year of life. The growth rate in the first six years is relatively high and identical in both sexes. From this point on, both sexes develop differently. In female animals, growth slows down from around the age of 10, while in males there is a significantly smaller increase in size from around the 15 year old. At around the age of four, young males begin their own excursions outside of the maternal herd. They spend less and less time with the family group and from the seventh to eighth year they form temporary associations on the fringes of the group or socialize with older bulls. The female offspring, on the other hand, remain in their herd for life.
The birth interval is 4.8 to 7.9 years, which is on average longer than that of the African elephant. Because of the long interval, cows have a birth rate of less than 0.2 calves per year. In the case of dams with male calves, this lasts longer on average than for those with female calves. The sex ratio at birth is 1: 1, but sometimes more male calves are born when a cow is born for the second time. The calves' survival rate is usually high. External environmental conditions have a major influence, as the optimal survival temperature for calves is around 24 ° C. At significantly lower temperatures, the general constitution of the young is decisive for survival, while higher temperatures lead to a greater risk of disease. Likewise, wetter seasons are associated with a higher survival rate than compared to drier ones. Male and female animals enter sexual independence between the ages of 14 and 16. According to studies in the Udawalawe National Park, young cows give birth to their first calf at an average age of 13.4 years; in the Pinnawela Elephant Orphanage , the first birth takes place at around 14.6 years of age. Anecdotal reports are also available from much younger pregnant animals (eight to nine years). The same applies to young bulls, in whom the first sperm can form at the age of seven or eight. However, young males usually have neither the physical requirements nor a socially dominant position for mating with cows. Female animals are able to reproduce up to an old age of around 60 years. The lifespan in the wild, limited by the last teeth, is around fifty to sixty years. Human care often shortens the lifespan of the Asian elephant. Reports from animals older than 80 years are unconfirmed. In the past, these were mostly caught in the wild, the age of which was unknown and estimated when they were caught.
Predators, parasites and ecology
Predators and interactions with other animal species
The Asian elephant has no natural predators. Occasionally the tiger will prey on a young animal. In the event of a threat, young animals are surrounded by adult group members. Occasionally, however, the predators also fall into adult individuals, as studies on cadavers in the Corbett Tiger Reserve in northern India show. Since the prey drops drastically here in the dry season, it is probably a reaction of the tiger to extreme external conditions. The Asian elephant seems to perceive the tiger as a predator . This is suggested by experiments with nocturnal roaring calls by the big cat, which led to the elephants quietly withdrawing. The Asian elephant reacted to the roar of a leopard by withdrawing, but combined this with loud growls and trumpets.
Several other large mammals are found in the Asian elephant range. Among other things, the Indian rhinoceros should be emphasized . Direct encounters between the Asian elephant and the Indian rhinoceros can lead to the defense action of the Indian rhinoceros. Cow elephants often evade, and bulls also react with attacks. In terms of diet, studies in the Nepalese Bardia National Park showed hardly any competition between the two species. During the dry season, the food of the Asian elephant consisted of 65% soft and 24% hard vegetable food. The food preference of the Indian rhinoceros was the opposite of that of the Asian elephant, as hard grass dominated over soft plant parts. Overlaps affected slightly more than a third of the food plants, the greatest similarities could be shown in the preference for saccharum as the main grass food .
Parasites
The external parasites include midges of the genus Culicoides , which normally infect the ear region and act as carriers of both filariasis and leucocytozoonosis . Other ectoparasites appear with flies such as Stomoxys , Chrysomya , Haematobia and Tabanus and with animal lice such as Linognathus . Internal parasites are roundworms of the genus Toxocara , various nematodes as Murshidia , Strongyloides , Enterobius , Quilonia , Amira or Bathmostomum , flukes such as Fasciola or tapeworms , so Anoplocephala represented. Variations have seasonal causes with a high infestation during the dry season and less in the rainy season. Usually cows are affected more often than bulls. A notable effect among bulls is that individuals with more developed tusks tend to be less likely to be afflicted by internal parasites. Occasionally, individual individuals become infected with foot and mouth disease as a result of direct or indirect contact with pets.
Ecological importance
As a major agent, the Asian elephant's impact on the landscape can be dramatic at times. It consists in opening and clearing forests, and also in a certain restructuring of the composition of a biotope . A single animal needs up to 150 kg of plant food per day. Calculated over the year, this corresponds to 27.5 to 55 t, depending on the size of the individual, or 10.5 t per square kilometer, depending on the efficiency of the food used. Another influence arises from the breaking of branches or kinking of trees that are not directly related to food intake. Locally, this can have a strong influence on the natural vegetation and, under certain circumstances, lead to the local extinction of certain preferred but less common food plants, such as Grewia and Desmodium species in Bardia National Park. On the other hand, this also stimulates the more intensive growth of other food plants, for example representatives of the genus Mallotus or Macaranga , which exploit the gaps in the forest created by the elephants. In principle, the interactions between long-lived creatures such as elephants and trees have not yet been adequately researched.
Like its African cousin, the Asian elephant plays an important role in spreading seeds. The seeds ingested with the fruit pass through the gastrointestinal tract in an average of 35 to 39 hours, with a maximum of 114 hours. Combined with the daily migrations of the Asian elephant, this means that the seeds are transported around 1.2 km on average before they reach the ground again through the manure excreta. In individual cases, distances of 5.7 km could also be proven. Among other things, acacias, tamarind trees and rose apple trees , whose fruits are relatively often eaten by the Asian elephant, benefit from this . Overall, depending on the region, it is involved in the distribution of 29 to over 60 plant species.
The species also fulfills an important ecological function in other areas, but studies have so far been rare compared to the African elephant. According to the food it consumes, an Asian elephant leaves up to 180 kg of faeces daily. The excreted manure is used as a retreat for a wide variety of living beings, including numerous insects such as beetles, for example frogs . The latter also spawn in water-filled step seals, which can sometimes remain for over a year and thus function as temporary still water areas. At the water holes pawed in the sandy river beds, other animals such as mongooses use fresh water. Likewise, on the elephant trails - which are partly free of vegetation and are sunk up to 7 cm into the ground through constant use and thus stand out clearly - there are also other larger mammals, various buffalos or sambars can be mentioned here .
Systematics
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Internal systematics of today's elephants according to Meyer et al. 2017
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The Asian elephant is a species from the genus Elephas and is the only recent representative. Elephas is the sister group of the African elephant ( Loxodonta ), which includes the African elephant ( Loxodonta africana ) and the forest elephant ( Loxodonta cyclotis ). The two species turn up, the current members of the family of elephants (Elephantidae) in the order of mammoths represent (Proboscidea). As a very old group originally of African animals, the origins of Russell animals about 60 million years into the past back. In the course of their tribal history, they proved to be very diverse and were adapted to numerous biotopes and climatic regions. Representatives of the proboscis colonized large parts of Eurasia and America . Compared to the long tribal history of the trunk animals, the elephants are to be seen as a relatively young line of development. Their earliest forms can be traced back to the late Miocene . Precursors of today's forms appeared in fossil form around 7 million years ago. According to molecular genetic analyzes , the two current genera separated from each other a good 7.6 million years ago. From a genetic point of view, however, the closest relatives of Elephas are not the African elephants , but the extinct mammoths ( Mammuthus ), which split off 6.7 million years ago. Both together form the tribe of the Elephantini , while the African elephants form the Loxodontini .
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Internal systematics of the Asian elephant according to Girdland et al. 2018 (based on genetic data)
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As a rule, three subspecies of the Asian elephant are recognized:
- E. m. indicus Cuvier , 1798 ( Indian elephant ); mainland Asia;
- E. m. maximus Linnaeus , 1758 ( Sri Lankan elephant ); Sri Lanka;
- E. m. sumatranus Temminck , 1847 ( Sumatran elephant ), Sumatra and Borneo;
The number of ribs is often given as a distinguishing feature between the mainland forms and the animals native to Sumatra, which is 20 in the former and 19 in the latter. In general, the internal system of the Asian elephant needs a revision. According to genetic analyzes, two clades ("α-clade" and "β-clade") can be distinguished within the species , which probably formed in the Old Pleistocene around 1.80 to 1.95 million years ago and then around 1.6 ("Β-clade") and about 0.9 million years ago ("α-clade") have differentiated further. This means that two separate taxonomic units of the Asian elephant could exist. Both clades are distributed over almost the entire continental distribution area, the "β-clade" also opened up the Malay island world. The animals of the Malay Peninsula and Sumatra form a separate subgroup within the "β-clade" ("β2-clade"), the origin of which also goes back around 0.9 million years ago. However, the data do not support the integrity of the Sri Lankan population , as individuals from the island are found in both clades. In certain areas of the distribution area there are hybrid formations between the two clades.
In some cases, three other subspecies are also listed, two of which, however, have recently become extinct:
- † E. m. asurus Deraniyagala , 1950 (" Syrian Elephant "); West Asia;
- E. m. borneensis Deraniyagala , 1950 (" Borneo dwarf elephant "); Borneo;
- † E. m. rubridens Deraniyagala , 1950; East Asia;
Systematic independence is problematic for all three forms, and they are often synonymous with E. m. indicus or E. m. maximus . The description of E. m. asurus is largely based on a molar from the swamp area of the al-Habbaniyya Lake west of Baghdad as well as on ancient representations. The presumed synonymy of the extinct form with today's representatives is supported by genetic data on around 5500 year old West Asian individuals, which correspond to one of the two recent clades ("β-clade") of the Asian elephant. The animals can thus be integrated into the range of variation of today's populations. The closest related group is found in Southeast Asia. Some scientists believe that the former occurrence of the Asian elephant in Western Asia is not endemic , but rather caused by prehistoric humans. According to this, the spread of the animals there would be a result of the demand for and use of raw materials by the Bronze Age cultures, which were brought in by younger individuals from the distribution areas further to the east. This view is underpinned by the previous finding that there was no evidence of a continuous colonization of Western Asia by the Asian elephant from the end of the Pleistocene to the developed Holocene. The disappearance of animals from the region at the beginning of the first millennium BC According to the researchers, this can be traced back to human-animal conflicts caused by the elephants' high need for food, on the one hand, and the rather inhospitable, desert-like conditions in West Asia, on the other hand, are not likely to have supported a large population of elephants.
A similar discussion concerns the animals of Borneo, whose current population is limited to the northeast of the island. Their origin is unknown, subfossil remains of elephants on Borneo are not documented. An introduction as domesticated animals by humans in the 17th or 18th centuries is often assumed. Some researchers consider the "Borneo dwarf elephant " to be the descendants of the elephants that were once widespread in Java and that became extinct in the course of the 14th century. In terms of body dimensions, the animals of Borneo do not differ from other representatives of the Asian elephant from the region, but on average they are slightly smaller than the members of the mainland populations. On the other hand, genetic studies can differentiate the elephants from Borneo from the other elephants in Asia. They are part of the "β-clade", but there is no closer genetic relationship with the animals from Sumatra and Malaysia. The separation from the other lines of the "β-clade" possibly began as early as the Middle Pleistocene around 300,000 years ago. Therefore, other researchers again suspect an endemic origin of the Borneo population. It then went through a severe slump in the past and has only recently recovered.
In addition to the Asian elephant, other extinct species are assigned to the genus Elephas :
- Elephas hysudricus Falconer & Cautley , 1845
- Elephas hysudrindicus Dubois , 1908
- Elephas planifrons Falconer & Cautley , 1845
- Elephas platycephalus Osborn , 1929
Tribal history
The genus Elephas appears comparatively late in the fossil record . Numerous African finds that were originally associated with Elephas (such as "Elephas" ekorensis , "Elephas" recki or "Elephas" iolensis ) are in the line of development of the genus Palaeoloxodon , which in turn has closer ties to the African elephants. This also includes various records from Eurasia , both of continental origin (for example "Elephas" antiquus and "Elephas" namadicus ) as well as from several islands in the Mediterranean (such as individual dwarf elephants such as "Elephas" falconeri ).
Clear early evidence of the genus Elephas can be found in the Siwaliks in South Asia , including tooth finds from the Nagrota and Uttarbaini Formations , whose age dates from 3.6 to 2.5 million years in the transition from the Pliocene to the Pleistocene . In general, the early forms are assigned to Elephas planifrons , a small representative of the genus. His teeth still had comparatively low crowns and, with 8 to 12 enamel folds, a relatively small number on the last molar. The enamel was thick and the frequency of the lamellae varied between 2.5 and 5.5. Other special features can be found on the skull with a wide and flat face area and a deep depression on the forehead. The occiput joints were relatively high, and the alveoli of the upper tusks were oriented more forward than downward. In the course of the Lower Pleistocene, Elephas planifrons was largely replaced by Elephas hysudricus , which appeared quite frequently. The form is not only documented in South Asia, where not only remains from the Siwaliks but also those from the Narmada river valley in central India have been handed down, but was also present in various sites in Western Asia , for example in the Levant . Sometimes there is a sympatric occurrence with representatives of Palaeoloxdon such as Palaeoloxodon antiquus (European forest elephant) or Palaeoloxodon namadicus . Elephas hysudricus is characterized by a higher lamella frequency of 3.9 to 6.5, which results in a larger number of enamel folds from 12 to 17 on the last molars. The teeth are generally rather high-crowned, as they exceed their width by up to 60%. In terms of skull structure, the species resembles today's Asiatic elephant, and is often viewed as a direct phylogenetic precursor. Both Elephas planifrons and Elephas hysudricus were scientifically introduced in 1845 by Hugh Falconer and Proby Thomas Cautley . Individual skull finds from the Siwaliks, which were only determined by Richard Lydekker in 1886, are considered to be the respective type material . The species Elephas platycephalus has only come down to us from a single find, a partial skull with severely chewed back molars, from near Shimla in northern India. The skull is characterized by a largely flat and elongated structure and thus appears primitive. Its exact age and its exact phylogenetic position are unclear. The species was introduced in 1929 by Henry Fairfield Osborn . Only a few years later, Osborn referred the species to its own genus under the name Platelephas , which is not recognized.
Individual other forms are known from the Malay island world . This includes Elephas hysudrindicus , which was found mainly on Java . Here the shape forms part of the important Kedung-Brubus fauna from the transition from the Lower to the Middle Pleistocene. The species goes back to Eugène Dubois from 1908, who did not present the underlying fossil material. Only subsequent authors did this. In individual characteristics, Elephas hysudrindicus shows mixed characteristics between Elephas hysudricus and Elephas maximus . This concerns, among other things, the higher number of lamellae (18 to 21) compared to the former (lamella frequency 6.5) and the moderately thick enamel, for example the larger skull in relation to the latter. Because of this, Elephas hysudrindicus is usually not placed in the direct predecessor of today's Asian elephant. "Elephas" celebensis is to be assessed as rather problematic . Originally built in 1949 by Dirk Albert Hooijer based single tooth finds of Sulawesi as Archidiskodon celebensis named the species was later mostly to Elephas directed. Due to the size of the teeth, it represents a dwarf form that was only half the size of Elephas planifrons . Just one year after Hooijer led Miklós Kretzoi with Stegoloxodon indonesicus another dwarf form of Java also based on tooth finds one. This was considered by later authors to be synonymous with "Elephas" celebensis . The central bulge of the enamel folds, which can be found similarly in the teeth of African elephants, is a striking feature. The number of enamel folds on the last molar is 8 to 11. More recent studies from 2008 tend to regard the genus Stegoloxodon as an independent genus and include "Elephas" celebensis in it alongside Stegoloxodon indonesicus .
Compared to the rather rich finds of older representatives of the genus Elephas , the remains of the Asian elephant are only rarely documented in fossil form. A single posterior molar from the north Indian state of Jammu and Kashmir with more than 22 enamel folds and a crown height more than twice the crown width could indicate the presence of the species as early as the Middle Pleistocene. The much larger part of the finds belongs to the Upper Pleistocene and is widely scattered across the Indian subcontinent. The remains from the river valleys of the Narmada or the Godavari can be highlighted . There are also individual fossils from Sri Lanka , for example from the Ratnapura River in the south of the island state. In particular, isolated teeth came to light on the Malay Peninsula . Their age is mostly unclear, they probably belong in the transition from the Upper Pleistocene to the Holocene . Several fossil remains have been documented from southern China , including those from the Quzai and Baxian caves in the Guangxi autonomous region . Here the Asian elephant appeared sympatric with representatives of the genus Stegodon during the Upper Pleistocene . According to isotope analyzes , Stegodon was more specialized in soft vegetable food, whereas the Asian elephant, as a generalist, ate both soft and hard vegetable food. According to this, the two forms of proboscis did not share a common habitat , as the former preferred rather dense forests, while the latter also appeared in more open landscapes.
Research history
The scientific name of the Asian elephant goes back to Linnaeus in 1758. In his important work Systema Naturae , Linnaeus listed the elephants of Africa and Asia under the name Elephas maximus and specified Ceylonae , today's Sri Lanka, as the type locality . The name Elephas is of Greek origin ( έλέφας ) with largely unknown origin. Possibly it comes from the Hebrew word ibah , which was conveyed via Sanskrit ( ibhas ) and can also be found in the Latin word ebur for "ivory". Was used Elephas already in ancient times, was referring to at the time but less on the animal itself and more on the tusks or ivory. As a superordinate name for all elephants, Elephas can already be found in John Ray in 1693, to which Linnaeus also referred in his Systema Naturae . The formal separation between the Asian and the African elephants was made by Johann Friedrich Blumenbach in his “Handbuch der Naturgeschichte” in 1797, where he listed the former under Elephas asiaticus , the latter under Elephas africanus . Blumenbach justified his step with differences in tooth construction.
In a later publication about the collection of the Swedish King Adolf Frederick in Stockholm from 1764 Linnaeus pointed to one in alcohol inserted embryo as a basis for drawing up the kind Elephas maximus . The specimen had already been mentioned and illustrated by Albert Seba in his work Thesaurus ; for a long time it represented the type specimen of the species. Seba had, however, indicated its origin as Africa. Genetic studies on the individual from 2014 determined an actual origin from Africa and identified it as an African elephant. The authors of the study therefore selected an almost complete skeleton, placed in the La Specola Museum in Florence, as the lectotype of the Asian elephant (copy number MZUF-734). This had already been mentioned by John Ray in 1693 and could be clearly assigned to the Asian elephant both morphologically and genetically. Presumably it is the historically documented elephant " Hansken ", who was born in Ceylon, today's Sri Lanka, in 1630 and died in Florence in 1655.
Linnaeus had already given the Asian elephant the name Elephas indicus a few years before it was first named . His authorship is not valid according to the rules of the ICZN . The species assignment was partly continued by other authors of the time, including Georges Cuvier in 1798. Like Blumenbach a year earlier, Cuvier differentiated the Asian elephant as Elephas indicus from the African elephant , for which he chose the name Elephas capensis (a synonym today to Loxodonta africana ). Although Cuvier did not give an area of origin for Elephas indicus , he established the current subspecies name for the mainland forms of the Asian elephant. During the 19th century the name Elephas indicus was used almost exclusively for the Asian elephant. This only changed in 1891 when William Thomas Blanford pointed out the priority of Elephas maximus . Almost 50 years later Coenraad Jacob Temminck coined the name Elephas sumatranus for the island forms of Sumatra .
Asian elephant and human
Local cultural aspects and taming
As the largest land mammal on the Asian continent, the Asian elephant found its way into people's cultural traditions early on. Early pictorial representations were made in the Upper Palaeolithic and can be found at the Jwalapuram site near Kurnool 180 km south of Hyderabad in central India. The reddish elephant depiction attached to a rock wall is 1.7 m long and 1.2 m high and forms part of an ensemble of several zoomorphic figures. The rock painting dates between 20,000 and 11,000 years ago. Individual hunting scenes in the Vindhya Mountains near Mirzapur , so near the Wyndham Falls or Morhana Pahar, in northern India are already Mesolithic . The taming of the Asian elephant, on the other hand, began much later, but exactly when it began is largely unclear. It is possible that engravings on seals of the Indus culture in the valley of the Indus speak for an early taming and use of the animals. The Indus culture developed in the period from 2600 to 1900 BC. And stands in the tradition of the Bronze Age . The number of seals with elephant motifs, however, is greatly reduced compared to other representations, from the two large cities Mohenjo-Daro and Harappa there are less than 50 in total. At this time, however, there was also a trade in ivory and art objects made from it, such as finds from the settlement Gonur Depe ( Turkmenistan ) of the neighboring oasis culture to the north .
At the latest after the fall of the Indus culture and the beginning of the Vedic period around 1500 BC. The Asian elephant must have been tamed on the Indian subcontinent. Classic literature like the Rig Veda from the 15th century. v. BC, the Upanishads from the 9th to 6th centuries BC And the Gaja-śāstra ( Sanskrit for "elephant science") from the 6th to 5th centuries BC. Chr. Document details about the capture, training and keeping of elephants. In addition to the Gaja-śāstra , a number of other Sanskrit works also deal intensively with the elephants, such as the Arthaśāstra and the Mātanga-līlā . At this time, the Indians differentiated between different castes of the Asian elephant, such as the stately Koomeriah , the slow and rather weak Manda , the lanky and nervous Meerga and a mixed type called Miśra (in a three-caste system these were named Koomeriah , Meerga and Dvásalain guided). The animals were mainly used in clearing to cut trees and carry wood from the clearings. As a result, they played an important role in the establishment of settlements. It is unclear whether they were included in the war back then. First Megasthenes , at the end of the 4th century BC. BC as a Greek diplomat at the court of Chandragupta Maurya , reports in his work Indika of supposedly 9000 elephants in the army of the Maurya Empire . The writing also gives insight into the taming and diseases of animals. An independent professional group, the mahouts , developed to deal with the working elephants . These special elephant trainers and guides have a close bond with their respective animals, some of which has lasted for decades. The tradition is usually passed on in the family to this day. Elephants trained over many years can obey between 20 and 30 command words, plus various tactile instructions.
From India, knowledge of how to tame the Asian elephant spread across South and Southeast Asia. The importance of the Asian elephant on the Indian subcontinent and in Southeast Asia is expressed above all in its religious significance, as evidenced by the elephant-faced god Ganesha in the Hindu faith or the legend of Siddharta Gautama in the Buddhist tradition. The Asian elephant found its way into temple architecture, among other things, as indicated by some outstanding examples such as the 360 m long terrace of the elephants or the elephant gate in Angkor , built during the Khmer kingdom from the 9th to 14th centuries. Also worth mentioning are the Sandakada pahana , so-called "moonstones", which, as semicircular structures in the entrance area, represent an important aspect of Sinhala architecture during the Anuradhapura and Polonnaruwa epochs from the 4th century BC. To the 13th century AD. Even in later times, during the Timurid rule in the 14th and 15th centuries or during the Mughal Empire from the 16th century, the Asian elephant was often used to represent imperial size.
In the western world, the Asian elephant became known relatively late. There are individual depictions of elephants from ancient Egyptian times, such as those in the grave chapel of Rechmire in Thebes-West from the 15th century BC. BC, who because of the small ears allow the Asian elephant to be adopted as a model, also killed Pharaoh Thutmose III. after the Battle of Mittani around 1446 BC According to tradition, up to 120 elephants on the way home on the way home, but exact descriptions of the animals did not appear before the Greco-Roman antiquity . Homer already mentioned elephants in his two epics, the Iliad and the Odyssey , but mostly only refers to the ivory or the tusks. In 416 BC Then the Greek scholar Ktesias of Knidos first described an Asiatic elephant at the court of the Persian great king Dareios II. During the battle of Gaugamela around 331 BC. Against the Persian king Dareios III. or in the Battle of the Hydaspes around 326 BC BC against the Indian king Poros , the Macedonians first learned of the efficiency of the Persian and Indian war elephants . The deployment of a large phalanx of 200 war elephants is documented for the latter battle . Alexander the Great saw this as an opportunity to build his own armed force from elephants. He captured over a dozen animals, which in turn gave Aristotle the opportunity to study the animals more closely. Aristotle dealt with elephants several times in his works De partibus animalium and Historia animalium , recognizing the importance and function of the trunk , as well as the fact that an animal would not survive without it. During the Diadochenkriege in following the death of Alexander the Great fell Perdikkas with the elephants in Egypt and was designed by Ptolemy I conquered. The Ptolemies took over Alexander's Asian elephants and later replaced them with African elephants, which they captured in what is now Eritrea . The attempts at taming the African elephant by the Ptolemies finally culminated in the Battle of Raphia around 217 BC. Against the Seleucids . As Asian and African elephants faced each other on the opposing side during this act of war, it is sometimes referred to as the "battle of the elephants". In the further course elephants were also used for entertainment and representation purposes. Famous is the inauguration of the first stone theater commissioned by Gnaeus Pompeius Magnus in Rome in 55 BC. BC, in which 20 elephants were slaughtered in addition to rhinos and various predators. Similar to the various realms in Central and South Asia, the Asian elephant had during the European colonial period of the Portuguese, Dutch and English from the 15th / 16th centuries. Century often representative character, individual animals were passed on as diplomatic gifts. The elephants " Hanno " as a gift to Pope Leo X and " Soliman " as a gift to Maximilian, the later Emperor Maximilian II of the Holy Roman Empire of the German Nation, are mentioned here .
Threat and protection
As with its African cousin, hunting is one of the greatest threats to the population of the Asian elephant. The hunt is not only focused on the ivory , it is also due to the meat, which serves as a food resource, and the skin, which is used in many ways. There are only a few studies on the actual level of threat. According to a 20-year study in Periyar National Park in southern India from 1974 to 1994, it is estimated that more than 3 tons of ivory were illegally captured during the period. The massive hunt meant that the sex ratio of males to females shifted from 1: 6 to 1: 122. As a result, not only did the absolute number of bulls decline, but the ratio of tusk-bearing to tusk-less animals also decreased relatively, as did the size of the tusks per individual. Similar development trends have also been published for other Indian protected areas. For other regions in the range of the Asian elephant the data situation is rather small. According to a study, over 60 elephants were illegally killed in Myanmar between 2010 and 2015 , 19 animals died in the south-central part of the country in 2016 alone, including seven that belonged to a study group equipped with radio stations. A total of 44 elephants were killed in Sumatra in the second half of the 2000s. Individual populations in the southern part of the island, for example in the Way Kambas National Park , are considered to be unable to survive.
In addition to illegal hunting and poaching, the destruction and sprawl of the habitat as well as the conversion into economic areas have a negative impact on populations. The range of the Asian elephant coincides with one of the most densely populated regions of the world. The high space and food requirements caused by the size of the animals and their social way of life lead to human-animal conflicts in many densely populated and / or agricultural areas in South Asia, which in turn lead to the destruction of fields, houses or the loss of human life have as a consequence. Between 1991 and 2001, around 150–230 deaths per year were recorded for all of India. In Sri Lanka , between 30 and 70 people die each year in clashes with elephants; between 2004 and 2005 alone, 975 registered conflicts occurred in the southeastern part of the island state. In Bangladesh, on the other hand, around 38 people lost their lives in 2001 and 2002, while in Vietnam alone around 26 people were killed in one place by elephants in 2002. In the densely populated province of Lampung in the south of Sumatra, over 700 conflicts with three people killed are reported for the period 2000 to 2002, and information is available on five people killed for the period 2005 to 2010. The reduction and avoidance of such conflicts is one of the greatest challenges for local and national nature conservation groups. Conflict solutions can be found in a wide variety of approaches, from physical barriers (fences, ditches) to deterrence (fire, noise, buffer zones with inedible plants) and resettlement or culling herds of elephants.
Estimates for the wild population of the Asian elephant range from 41,400 to 52,300 individuals, data obtained in 2003. A good half of this is in India, for the other around a dozen countries in which the Asian elephant is native, the data vary between 70 and 250 individuals (e.g. China , Vietnam and Bangladesh) up to 2500 and 5000 individuals (e.g. Sri Lanka , Myanmar or Thailand ). There are also around 14,500 to 16,000 tamed animals. Here, too, the number is distributed quite differently, for Myanmar it is estimated at around 6000, for Laos at around 480. The reproductive rate of the animals in captivity is rather low, which can lead to the extinction of the domesticated populations. Therefore, in Myanmar alone, around 100 individuals have to be procured annually from the wild to maintain this number. This practice results in an additional threat to wild populations. Overall, the IUCN is assuming a general decreasing trend for the latter, according to surveys, the reduction in the last three elephant generations (20 to 25 years each) was around 50%. The decline is connected with the loss of habitat and the reduction in habitat characteristics . The nature conservation organization therefore classifies the species as "threatened" ( endangered ). Measures for their preservation consist in the protection of the habitat including the creation of migration routes or corridors, in the resolution of human-animal conflicts as well as in better protection of animals, among other things through trade bans and a strengthening of local and international legislation. The Asian elephant is listed in Appendix I of the Washington Convention on Endangered Species . This prohibits supra-regional and international trade as well as cross-border transfer of living specimens and body parts without the approval of the competent national authorities.
literature
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Individual evidence
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- ↑ Bernhard Rensch and Rudolf Altevogt: The degree of visual learning ability of an Indian elephant. Zeitschrift für Tierpsychology 12 (1), 1955, pp. 68-76
- ^ Lynette Hart and Sundar: Family traditions for Mahouts of Asian elephants. Anthrozoös 13 (1), 2000, pp. 34-42
- ↑ HIE Katugaha: Elephants in stone. Gajah 20, 2001, pp. 63-65
- ^ Noel Hidalgo Tan: Elephants in South-East Asian Rock Art, an Overview. In: Anura Manatunga, KAT Chamara, Thilina Wickramaarachchi and Harini Navoda de Zoysa (Eds.): International Conference on Asian Elephants in Culture & Nature, 20th - 21st August 2016. University of Kelaniya, Sri Lanka, 2016 (abstracts)
- ^ A b Raman Sukumar: The Human-Elephant Relationship through the Ages: A Brief Macro-Scale History. In: Piers Locke and Jane Buckingham (Eds.): Conflict, Negotiation, and Coexistence: Rethinking Human-Elephant Relations in South Asia. Oxford, 2016; doi: 10.1093 / acprof: oso / 9780199467228.001.0001
- ↑ Diamantis Panagiotopoulos: Foreigners in Egypt in the Time of Hatshepsut and Thutmose III. In: EH Cline and D. O'Connor (eds.): Thutmose III. A New Biography. Ann Arbor, 2006, pp. 370-412
- ↑ Merlin Peris: Aristotle's Notices on the Elephant. Gajah 22, 2003, pp. 71-75
- ^ Lionel Casson: Ptolemy II and the hunting of African elephants. Transactions of the American Philological Association 123, 1993, pp. 247-260
- ^ HJ Gehrke: Alexander the Great. CH Beck, Munich, 1996 ISBN 3-406-41043-X ( [24] )
- ↑ Michael B. Charles: Elephant Size in Antiquity. DNA Evidence and the Battle of Raphia. Historia 65 (1), 2016, pp. 54-65
- ↑ Pierre Schneider: Again on the elephants of Raphia: Re-examination of Polybius' factual accuracy and historical method in the light of a DNAsurvey. Histos 10, 2016, pp. 132-148
- ^ Jo-Ann Shelton: Elephants, Pompey, and the reports of popular displeasure in 55 BC. In: Shannon N. Byrne and Edmund P. Cueva (Eds.): Veritatis Amicitiaeque Causa: Essays in Honor of Anna Lydia Motto and John R. Clark. Wauconda, Illinois, 1999, pp. 231-271
- ^ R. Sukumar, Uma Ramakrishnan and JA Santosh: Impact of poaching on an Asian elephant population in Periyar, southern India: a model of demography and tusk harvest. Animal Conservation 1, 1998, pp. 281-291
- ↑ Christie Sampson, John McEvoy, Zaw Min Oo, Aung Myo Chit, Aung Nyein Chan, David Tonkyn, Paing Soe, Melissa Songer, A. Christy Williams, Klaus Reisinger, George Wittemyer and Peter Leimgruber: New elephant crisis in Asia - Early warning signs from Myanmar. PLoS ONE 13 (3), 2018, p. E0194113; doi: 10.1371 / journal.pone.0194113
- ↑ Simon Hedges, Martin J. Tyson, Arnold F. Sitompul, Margaret F. Kinnairda, Donny Gunaryadi and Aslan: Distribution, status, and conservation needs of Asian elephants (Elephas maximus) in Ampung Province, Sumatra, Indonesia. Biological Conservation 124, 2005, pp. 35-48
- ↑ a b Wahdi Azmi and Donny Gunaryadi: Current status of Asian Elephants in Indonesia. Gajah 35, 2011, pp. 55-61
- ↑ K. Ullas Karanth and MD Madhusudan: Mitigating human-wildlife-conflicts in Southern Asia. In: John Terborgh, Carel van Schaik, Lisa Davenport and Madhu Rao (eds.): Making parks work. Strategies for preserving tropical nature. Washington / Covelo / London, 2002, pp. 250–264
- ^ R. Sukumar: The Living Elephants: Evolutionary Ecology, Behavior, and Conservation. Oxford University Press, 2003, pp. 1-477 (pp. 298-351)
- ↑ Ahimsa Campos-Arceiz, Seiki Takatsuki, Sampath KK Ekanayaka and Toshikazu Hasegawa: The Human-Elephant Conflict in Southeastern Sri Lanka: Type of Damage, Seasonal Patterns, and Sexual Differences in the Raiding Behavior of Elephants. Gajah 31, 2009, pp. 5-14
- ↑ a b c d B. MA Oswin Perera: The Human-Elephant Conflict: A Review of Current Status and Mitigation Methods. Gajah 30, 2009, pp. 41-52
- ^ Ingrid Colette Suter, Gilles Pierre Maurer and Greg Baxter: Population viability of captive Asian elephants in the Lao PDR. Endangered Species Research 24, 2014, pp. 1-7
- ^ CITES: Convention on International Trade in Endangered Species of Wild Fauna and Flora. Text of the Convention. ( Article III: Regulation of Trade in Specimens of Species Included in Appendix I. ) Signed at Washington, DC, on March 3, 1973; Amended at Bonn, on June 22, 1979
Web links
- Elephas maximus in the endangered Red List species the IUCN 2010. Posted by: A. Choudhury, DK Lahiri Choudhury, A. Desai, JW Duckworth, PS Easa, AJT John Singh, P. Fernando, S. Hedges, M. Gunawardena, F. Kurt, U. Karanth, A. Lister, V. Menon, H. Riddle, A. Rübel & E. Wikramanayake (IUCN SSC Asian Elephant Specialist Group), 2008. Retrieved November 12, 2018.
- Video: Elephas maximus - step . Institute for Scientific Film (IWF) 1954, made available by the Technical Information Library (TIB), doi : 10.3203 / IWF / E-1 .