Spotted hyena
| Spotted hyena | ||||||||||||
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Spotted hyena ( Crocuta crocuta ) |
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| Crocuta | ||||||||||||
| Kaup , 1828 | ||||||||||||
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| Crocuta crocuta | ||||||||||||
| ( Erxleben , 1777) |
The spotted hyena or spotted hyena ( Crocuta crocuta ) is a species of predator from the hyena family (Hyaenidae). It is the largest hyena species and is characterized by its eponymous spotted fur; Another characteristic is the "masculinization" of the female genital tract . The species colonizes large parts of Africa and feeds mainly on larger, self-killed vertebrates. Spotted hyenas live in groups with a complex social structure, which can contain up to 130 animals and are dominated by females. The young animals, which are well developed at birth but suckled for over a year, are raised in community buildings.
features
General build and coat
Spotted hyenas reach a head body length of 125 to 160 centimeters, the tail is relatively short with 22 to 27 centimeters. The shoulder height is 77 to 81 centimeters. The weight is usually 45 to 60 kilograms, individual animals can weigh up to 86 kilograms. Females and males differ only slightly from one another and not in all body dimensions. Females are 2.3% longer and have slightly larger skulls and chest girths but no longer legs than males. This low gender dimorphism is said to vary regionally and be more pronounced in southern Africa than in other regions of the continent.
The fur is relatively short and rough, and the long mane on the back of the spotted hyena is less pronounced than that of the other hyena species. The relatively fine wool hairs are 15 to 20 millimeters long, the coarser outer hairs 30 to 40 millimeters. The basic color of the fur is sand yellow to reddish brown; on the back, on the flanks and on the legs there are numerous black and dark brown spots. These will turn brownish or fade with age. As with all hyenas, the front legs are longer and stronger than the rear legs, causing the back to slouch backwards. The front and rear paws each end in four toes, which are provided with blunt, non-retractable claws . Like all hyenas, spotted hyenas are digitigrad (toe walkers). The tail ends in a black, bushy tip; their hair protrudes from the end of the tail spine by around 12 centimeters.
Glands on both sides of the anal canal secrete a secretion to the anal sac located between the anus and the tail . The secretion is released from this anal bag when the area is marked. The females usually have only one pair, rarely two pairs of teats. As with all hyenas, the males lack penis bones .
Although hyenas are visually similar to dogs, they are more closely related to cats.
Masculinization
One of the most extraordinary characteristics of the spotted hyena is the masculinization ("masculinization") of the females. The peculiarity of the anatomy of the external female genital organs was the cause of speculation until the 20th century. The first scientific-anatomical description was published in 1877. The females have no vaginal vestibule and no vulva . The uterus has two horns and the body of the uterus is partially divided by a septum ( uterus bicornis subseptus ). The cervix is only a few millimeters long and indistinct. The vagina fuses - as otherwise only in male mammals - with the urethra to form a urinary genital duct (urogenital canal) that runs through the clitoris . The clitoris resembles the penis of the male, it reaches around 90% of its length and is also erectable . Urination, copulation and childbirth thus take place through this urogenital canal. It differs from the penis in the absence of the erectile tissue of the urethra , a strong folding of the mucous membrane and the different insertion of the retractor muscle ( retractor penis or clitoridis), which in males attaches to the underside of the penis and in females to the side surface of the clitoris. These factors enable the relatively large puppies, weighing up to 1.6 kilograms, to pass through to birth. Due to the special anatomical conditions, the birth canal has a 180 ° bend at the pelvic outlet, which occasionally leads to birth problems. The labia grow together and resemble the scrotum (scrotum) of the male (pseudoscrotum). The sexes can be differentiated by the shape of the tip of the penis or the clitoris: Males have a pointed glans , which makes copulation easier, while the tip of the clitoris is blunt at the front.
The physiological cause of this "masculinization" is not - as previously assumed - solely in the fact that the fetuses are exposed to androgens in the early stages . In experiments, pregnant females were treated with anti-androgens without the newborn females exhibiting a mammalian clitoris or an open vagina. In the newborn males the penis resembled the outside of the clitoris. The androgens, however, influence behavior and rank: higher-ranking females have a higher androgen level than lower-ranking animals in the final phase of gestation; their newborn pups are more aggressive.
The evolutionary reasons behind masculinization are not clear. Some authors suggest that the erect genital greeting ritual (see below ) is so important for group cohesion that the females benefit from participating in it. Another view regards masculinization as a “by-product” of the development of females towards stronger, more aggressive animals, which is an advantage when growing up in confrontations with siblings and in the struggle for food resources. Ultimately, however, it remains difficult to understand the evolutionary steps that led to this unique phenomenon among mammals.
How difficult it is to determine the sex of these animals is shown by a case from the mid-2010s from the Erfurt Zoo. When he wanted to breed hyenas, it was found that in other zoos that were already breeding, the males are smaller than the two males in Erfurt. Only a genetic examination then showed that no females are needed for breeding in Erfurt, since both “males” are actually females. They kept their names anyway. It is astonishing, however, that neither in the zoo, from which the animals originate, nor in Erfurt, could the sex be correctly determined without genetic testing.
Head and teeth
The structure of the skull and the teeth of the spotted hyena resembles that of the other real hyenas . The massive skull sits on a long, muscular neck, the muzzle is hairless and broad. The eyes have a tapetum lucidum to adapt to the twilight and nocturnal way of life , the ears are rounded in contrast to the other hyena species. The jaws are strong, the strong jaw muscles, especially the temporalis muscle , have a high sagittal ridge on the skull as a point of attachment. Thanks to their extraordinary jaw apparatus, spotted hyenas can develop biting forces of over 9,000 Newtons .
The tooth formula is I 3/3 - C 1/1 - P 4/3 M 1/1, so you have a total of 34 teeth. The incisors are inconspicuous, the canines are somewhat elongated. The premolars, which are adapted to the breaking of bones, are greatly enlarged and strongly built. The enamel is what prevents breakage of the teeth of a complex structure. The upper third and lower third premolars are primarily used to break bones. As in all land carnivores , the fourth upper premolar and the lower molar are developed into fangs ; these teeth are blade-shaped and are used to cut meat.
distribution and habitat
Spotted hyenas are native to large parts of Africa south of the Sahara , and their range extends from the Sahel to South Africa . In western Africa the distribution is fragmented, where the species hardly occurs outside of protected areas. In large parts of eastern and southern Africa, the distribution area is contiguous. The largest populations live in the East African Serengeti and in the Kruger National Park . In some areas they are extinct, for example in Algeria , where they lived in the Ahaggar and Tassili n'Ajjer mountains , or in central and southern South Africa. However, they are returning to some regions, for example the first animal in around 50 years was spotted in the Ivindo National Park in Gabon at the beginning of the 21st century.
Spotted hyenas are not picky about their habitat and occur, for example, in semi-deserts, savannas, open wooded areas and also in mountain forests. In the highlands of Ethiopia they can be found up to an altitude of 4100 meters. The animals avoid pure deserts and deep rainforests such as parts of the Congo Basin . They show little fear of people and can also be found near villages and other settlements.
Way of life
Activity times and territorial behavior
Spotted hyenas are predominantly crepuscular and nocturnal; they seldom go looking for food during the day at low temperatures. You spend around a third of a 24-hour day actively; the activity phase is not continuous, but is divided into smaller breaks. They cover between 12 and 40 kilometers in one night. During the day they sleep on the ground, often hidden in a bush when it is very hot. Young animals are raised in community buildings that have previously been raised by other animals such as B. the real porcupines or aardvarks were dug. These tunnel systems are expanded by the young animals and, since the entrances are too small for large predators, offer effective protection against them.
One group lives in a fixed territory , the size of which depends on the food supply. Territories in the rich savannahs of eastern Africa are often only 20 km² in size, while in the arid regions in the south of the continent they can be up to 1500 km². The boundaries of the area are sporadically paced by several group members and marked with glandular secretions. In doing so, they secrete a pungent, yellowish liquid from their anal pouch, which they rub in a half-crouching position on tufts of grass or similar objects. Sometimes they also mark the interior of their territory, but far less often than the other hyena species. Other glands that release scented secretions are located between the front toes. Scratching releases the secretions. These scratch marks can often be found in latrines in which members of a clan defecate together. The latrines consist of a collection of excrement and reach a diameter of over 10 meters. They are usually laid out along the borders and visited during the joint patrol of the area.
Both sexes defend the territory against non-group animals, but the females more intensely than the males. Intruders are hunted to the boundaries of the territory. This can lead to violent arguments between neighboring groups; these are far more common in areas with a high population density. Territorial behavior can change significantly in areas where there are few prey animals available all year round, but where large herds of herbivores migrate throughout the year. Spotted hyenas can undertake long migrations from their territory to their prey. Resident hyenas tolerate migrating groups as long as they do not start hunting in their territory.
Social behavior
Spotted hyenas live in groups called " clans ", which are made up of five to 130 animals. Small clans include a group of related females and a reproductive male; larger groups can consist of several females with their offspring, so-called matrilines , and several males. While the females usually remain in their birth group for life, most young males leave this group after sexual maturity at around 3.5 years of age. The adult males in the clans have therefore mostly immigrated and are not related to the females.
The social behavior of spotted hyenas is unique among predators ; it is much more similar to that of some Old World monkeys , such as baboons . The clans are organized according to the "fission fusion principle" (separate and come back together). All clan members know each other, they share a common territory and raise the young in a common den, but they spend a lot of time alone or in small subgroups, similar to chimpanzees .
The members of a clan establish a clear hierarchy which, among other things, applies to access to food resources. In contrast to other socially living animals, the rank of a hyena within the clan does not depend on its size, fighting ability or aggressiveness, but on the social support of other clan members. Spotted hyenas are particularly strong supporters of clan members who are closely related to them. As a result, hyenas, who have a particularly large number of offspring and other close relatives, have an advantage and occupy the highest positions in the clan hierarchy. Immigrant males occupy the lowest ranks because they lose their social ties when they emigrate from their ancestral clan. Since significantly more males than females migrate, a female is usually the highest-ranking animal in the clan and females are more often dominant over males than the other way round. It should be noted that the sons of high-ranking females, like their sisters, have a social rank just below that of their mother and that all lower-ranking clan members, including the females, dominate as long as they are members of their birth group.
The relationships and ranks between the matriculation lines are stable for many years. Young spotted hyenas “learn” their social rank in the hierarchy from their mother and other close relatives during their youth through encounters with other clan members. The juvenile hyenas initially attack both higher and lower-ranking clan members. In interactions with lower-ranking animals, they are supported by their mother and through this they learn in the first year of life to only attack clan members who are lower-ranking than their mother. Therefore, interventions by higher-ranking females are more frequent and more effective than those of lower-ranking animals. Another way to achieve a higher rank is through alliances with other group members - these can, but do not have to be, siblings. With these alliances it can often be observed that animals tend to take the side of the already stronger animal.
When a male immigrates to a group, regardless of his size or fighting strength, he initially takes the lowest rank. Advancement in the hierarchy is only possible if a higher-ranking male dies or leaves the group - the highest placed male is therefore the one who has been present in the group the longest. Around 40% of all males later leave the group to which they immigrated; the reasons for this are not known.
The social rank in the clan hierarchy has a great influence on the life of a hyena. High social status hyenas have preferential access to food, water, community burrows, and resting places, and they survive longer and produce more offspring than lower-ranking animals. The mother's social rank also determines the growth and survival of the offspring. Mothers with a high rank usually secure a particularly large proportion of snatched prey and are therefore better nourished than low-ranking mothers. As a result, the offspring of high-ranking mothers grow up faster and survive better than the less privileged offspring of lower-ranking mothers. The mother's influence also has a strong long-term effect on the offspring, because high-born daughters and sons father their first offspring earlier and have more offspring themselves than low-born hyenas.
communication
The most important form of communication is olfactory communication , that is, by means of smells. With the help of the anal bag secretion, the hyenas can identify the sex, degree of reproduction and group membership of another animal.
Like all real hyenas , spotted hyenas have their own greeting behavior. This welcoming ritual is an important mechanism that facilitates the transition between solitary behavior and life in groups and strengthens cohesion within the clan. The animals stand next to one another looking in opposite directions; then they raise one hind leg and sniff or lick the genital and anal regions of the other; the subordinate animal always lifts its hind leg first. The erect penis or clitoris plays an important communicative role, which expresses submission. Young animals from the age of four weeks can participate in this greeting behavior and straighten their sexual organs. If there is tension or excitement within the group, the number of these greetings increases; they could also play a reconciling role, for example after a dispute over food.
In contrast to the other hyena species, which hardly make any sounds , spotted hyenas have a rich repertoire of phonetic communication. The most commonly heard sound is a loud wuup that can be heard over a distance of several kilometers. This sound has several functions, it serves to call the group members together to defend the territory, to indicate a food supply or to indicate danger. With this sound, mothers call for their young animals and hungry young animals that want to be suckled for their mothers. This sound can also be used to find a partner. There are also deep grunting noises that urge the young to leave the building, high-pitched crying noises from the young that signal hunger, and a cow-like sound that puts the group members in a state of excitement. Finally, the laughing or giggling sound, which is similar to human laughter, is known. This laugh expresses submission and signals that the animal is accepting a lower rank.
Nutrition and Food Competitors
In contrast to the striped hyena and the black hyena , the other two species of real hyenas, spotted hyenas are skilled hunters who hunt between 60% and 95% of their prey themselves. They are very flexible about both the prey they eat and the methods of getting food. In addition to self-killed animals, they also eat carrion and practice kleptoparasitism , which means that they hunt prey from other carnivores.
Their food spectrum ranges from caterpillars to elephants , they are opportunistic and consume almost all mammal, bird, reptile or fish species that occur in their habitat. Bird eggs - which they kick and do not bite - are just as much on their menu as flying insects that they snap out of the air, and they occasionally eat plant material. Mostly, however, the medium-sized to large ungulates represent the main component of the diet. In East Africa these are blue wildebeest , zebras , gazelles and lyre antelopes ; in the arid south of Africa gauntlets ; Impalas in Kruger National Park and red-fronted gazelles and hartebeest in western Africa . In contrast to the cats, they don't sneak up on their prey, but rely on their perseverance. They reach speeds of up to 55 km / h and keep a hunt at a slightly lower speed for several kilometers. Spotted hyenas hunt individually or in packs, the group size depends on the prey. Smaller prey such as gazelles but also prey that weigh two to three times that of a spotted hyena, such as lyre antelopes and wildebeest , are usually hunted individually or in pairs. Larger prey such as zebras and buffalo are brought down by up to 30 hyenas. Smaller prey animals are killed with a killing bite, larger ones are often torn apart while they are still alive.
Live prey animals are localized by means of sight, hearing or smell. They find carrion by the smell, by the noises that other carnivores make, and in daylight also by watching vultures . Thanks to their good sense of smell, they can still detect carrion at a distance of 10 kilometers.
Even if the hunting parties are small, many animals often gather around one carcass. The noise attracts other group members, and within a short time over 30 animals can come together. The food competition between spotted hyenas of the same and other clans and with lions is very great in many areas. That is why the animals eat as much meat as possible in a short time; thanks to their strong teeth, they can break even thick bones. Their efficient digestive system uses all parts of an animal's body except for their hair, including their hooves and horns, according to some research. This makes spotted hyenas the most effective scavengers according to the Guinness Book of Records . A group of 20 to 30 spotted hyenas can completely devour a wildebeest in 13 minutes, except for a few small remains. On average, the animals eat 1.5 to 3.8 kilograms of meat per day; with a very large food supply, however, they can gobble down 18 kilograms of meat in an hour.
Kleptoparasitism has been observed against jackals , cheetahs , leopards , African wild dogs , striped hyenas and black- tailed hyenas. The most common food competitors of the spotted hyenas are lions . These two species are sympatric in much of Africa , and food thefts occur in both directions. Typically, lions are stronger and will drive spotted hyenas away from carcasses. But if the group of hyenas is large enough - around four times as many spotted hyenas as female lions - it can in turn drive the lions away. But if a fully grown male lion is present, the lions always have the upper hand. Sometimes the inferior animals wait until the winners have eaten their fill and then eat the carrion. In areas where there are far more spotted hyenas than lions, such as Ngorongoro Crater , lions are more likely to eat carrion from hyenas than vice versa. In other regions, like the Kruger National Park, the opposite is the case.
Reproduction
Mating can take place all year round. In the courtship behavior of the males it becomes clear that on the one hand they are willing to reproduce, on the other hand they are afraid of the female and would rather run away. The male therefore carefully approaches the female with several bows and then draws back again. Ultimately, the female decides whether copulation takes place. Due to the special structure of the genital tract, it is impossible for male spotted hyenas to force copulation, which can be quite common in other mammals. If the female is not ready to conceive, she will take no notice of the male's courtship or even meet him aggressively.
The oestrus lasts one to three days. The female indicates her fertility by reducing her aggressiveness and placing her mouth close to the ground. Mating, which occurs through the female's clitoris, consists of several copulations and ejaculations. Many copulations do not lead to fertilization. Both the male and the female reproduce with multiple partners. The males try to prevent this by guarding the female. Other males try to establish friendly relationships with the female and thus increase the chance of producing offspring with her. Basically, mating behavior is variable, and different males prefer different tactics. Around 25 to 30% of all twin litters are produced by more than one male.
After a gestation period of around 110 days, the female usually gives birth to two, sometimes one or three young animals. Birth also occurs through the clitoris, which tears in the process, leaving a bleeding wound that takes weeks to heal. The newborns weigh around 1 to 1.6 kilograms and have black fur. At birth, their eyes are open, the incisors and canines of the deciduous teeth are already there, and they are capable of coordinated movements within a few minutes. Compared to other predators and also other hyena species, they are well developed. The young animals spend the first two to five weeks in their own burrow, the following weeks in a communal burrow.
As all females in a group usually reproduce, there can be up to 30 young from 20 litters in a community building. Each female nurses only her own young and rejects the advances of other young animals. The milk of the spotted hyenas has the highest protein content of all land carnivores at 14.9% , and the fat content is only exceeded by some bears and sea otters at 14.1% . Due to the high energy content of the milk and the long period of breastfeeding, female spotted hyenas invest more energy in their offspring than any other predator.
Just a few minutes after birth, the young animals begin to fight aggressively with one another. These fights often lead to wounds of the inferior siblings, and sometimes siblicide occurs - that is, siblings kill each other. But this is not the rule. In these fights, the young animals establish a hierarchy that comes into play in better access to breast milk.
At five to six weeks, the fur of the young begins to take on the adult color, which is completed at four to five months. They stay in the community building for eight to twelve months, then they go for the first time on forays through the group's territory, initially accompanied by their mother, later alone. As with the other real hyenas, the breastfeeding period lasts a very long time: the young are usually weaned at 13 to 14 months, but lower-ranking females sometimes suckle their offspring for up to two years.
Around 50% of all young animals die before they reach sexual maturity; mortality is highest immediately after weaning. Males become sexually mature at around two years of age, at which point they have to leave their birth group. The females carry their offspring for the first time in their third or fourth year of life. In the wild, spotted hyenas live to be around 20 years old; the highest known age of an animal in human care was 41 years.
Spotted hyenas and humans
Spotted hyenas have an ambivalent reputation among the African population. On the one hand they are considered stupid, cruel and dangerous, on the other hand they are also cunning, strong animals. In the mythology of the tabwa from eastern Africa, a spotted hyena brought the sun to warm the earth. Hyena masks are used in the Bamana and Yoruba ceremonies, while the Yoruba use the animals as a sign of the end, as they remove the remains of the carcasses. Some tribes even leave their dead for the animals to eat.
In the western world, these animals have a bad reputation. This is how Alfred Brehm writes in Brehms Tierleben :
“In the regions I have traveled through, I have only come to know the spotted hane as a cowardly animal that shyly avoids people. She wears her head low with a bowed neck; the look is malicious and shy. [...] Among all the beasts of prey it is undoubtedly the most misshapen and nasty phenomenon; but to this come the spiritual qualities to make the animal hateful. "
Until the 20th century, spotted hyenas were sometimes thought to be hermaphrodites or were assumed to change their sex every year. The claim that this error goes back to the Historia animalium of Aristotle is wrong. On the one hand, the species description makes it clear that he is talking about the striped hyena , which is much more obvious since these animals are found in the Mediterranean region. On the other hand, he refutes this claim.
The image of the spotted hyenas is often based on their reputation for eating people or pets. In fact, they do occasionally kill people, for example when they sleep outside without protection. Often times, they also invade pastures and tear down pets. For these reasons, they are persecuted, either with firearms, with traps or with poison bait. But these actions also affect other carnivores such as cheetahs and jackals. However, only a few hyenas fall victim to sport hunting, as they are not an attractive trophy. Road traffic and the destruction of their habitat are further threats. One of the main problems with the implementation of protective measures is the negative image of animals.
Total spotted hyena populations are declining due to hunting and other factors, but not yet to a worrying extent. They have a large range and are very diverse in terms of their habitat and way of life, and are therefore less sensitive to human disturbance than other predators. The International Union for Conservation of Nature IUCN lists the species as “not endangered” ( least concern ) and estimates the total population at 27,000 to 47,000 animals. This makes them not only the most common hyena species, but also by far the most common large carnivore species on the African continent.
Systematics
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Internal classification of the genus Crocuta Westbury et al. 2020
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The Tüpfelhyäne is the only extant species of the genus Crocuta and together with the strip and the brown hyena the subfamily of authentics hyenas (Hyaeninae), which are characterized for example by strong teeth. The spotted hyena is the sister taxon of a common clade of striped hyena and saddleback hyena; the lines of development to this clade separated around 8.6 million years ago. Despite some variance in body size and coat color, no subspecies of the spotted hyena are distinguished, so the species is monotypical .
When today's spotted hyena ( Crocuta crocuta ) emerged as a species is not entirely clear. The earliest fossils suggest an age of around a million years. The first fossils of the genus Crocuta are much older and come from Africa from the early Pliocene , around 3.7 million years ago. They are assigned to the species Crocuta dietrichi . In the Pleistocene the genus reached its greatest distribution and occurred almost in all of Eurasia and Africa. The cave hyena ( Crocuta crocuta spelaea ), which is also the most well-known fossil form, has been handed down from numerous caves and open-air sites in Eurasia . This animal differed from today's spotted hyenas, among other things, by its shorter limbs; it was not yet adapted to fast running to the same extent. Usually it is classified as a subspecies of the spotted hyena, rarely as a separate species.
Genetic analyzes of fossil and recent members of the genus Crocuta show, however, that the situation is more complicated. Four different haplotype groups can be distinguished within the genus Crocuta : an African (group C), an East Asian (group D), a European (group B) and a mixed African-European (group A). As a result, the African spotted hyenas differ from each other north and south of the equator, but some of the Pleistocene cave hyenas from the area between Europe and the Altai Mountains belong to the same clade as today's North African forms. Accordingly, even the subspecies status of the cave hyena would not be justified in the strict sense. There has probably been a genetic exchange between Africa and Eurasia at least three times since the Pliocene, most recently a maximum of 360,000 years ago. However, this exchange of genetic material need not have prevented the development of special characteristics of the cave hyena. Investigated specimens from East Asia differ significantly from the African and West Eurasian forms. The earliest fossil finds of the genus Crocuta outside Africa are with Crocuta honanensis from the Longdan Basin in the Chinese province of Gansu . Their age is around 2 million years. From a genetic point of view, the separation between the African and East Asian representatives of the genus Crocuta occurred around 2.5 million years ago. Presumably during this period the first Crocuta -like hyenas left the African area for Eurasia. The cave hyena became extinct at the end of the Pleistocene.
literature
- Kay E. Holekamp and Joseph M. Kolowski: Family Hyaenidae (Hyenas). In: Don E. Wilson, Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 1: Carnivores. Lynx Edicions, 2009, ISBN 978-84-96553-49-1 , pp. 234-261.
- Ronald M. Nowak: Walker's Mammals of the World . Johns Hopkins University Press, 1999 ISBN 0-8018-5789-9
- Hans Kruuk: The Spotted Hyena. A Study of Predation and Social Behavior . The University of Chicago Press, 1972 ISBN 0-226-45507-6
Individual evidence
- ↑ Figures from Holekamp & Kolowski (2009), p. 254.
- ^ A b Eli M. Swanson, Teresa L. McElhinny, Ian Dworkin, Mary L. Weldele, Stephen E. Glickman: Ontogeny of sexual size dimorphism in the spotted hyena (Crocuta crocuta) . In: Journal of Mammalogy . tape 94 , no. 6 , December 16, 2013, ISSN 0022-2372 , p. 1298-1310 , doi : 10.1644 / 12-MAMM-A-277.1 ( oxfordjournals.org [accessed October 20, 2016]).
- ^ M. Watson: On the female generative organs of Hyaena crocuta . In: Proc Zool Soc Lond 1877, pp. 369-379.
- ↑ a b c Gerald R. Cunha, Yuzhuo Wang, Ned J. Place, Wenhui Liu, Larry Baskin and Stephen E. Glickman: Urogenital System of the Spotted Hyena (Crocuta crocuta Erxleben): A Functional Histological Study . In: Journal of Morpholgy 256 (2003), pp. 205-218. PDF
- ↑ CM Drea, ML Weldele, NG Forger, EM Coscia, LG Frank, P. Licht and SE Glickman: Androgens and masculinization of genitalia in the spotted hyaena ( Crocuta crocuta ). 2. Effects of prenatal anti-androgens. In: Journal of Reproduction and Fertility 113 (1998), pp 117-127.
- ↑ SM Dloniak, JA French and KE Holekamp: Rank-related maternal effects of androgens on behavior in wild spotted hyaenas. In: Nature 440 (2006), pp. 1190-1193.
- ^ A b c S. E. Glickman, CJ Zabel, SI Yoerg, ML Weldele, CM Drea and LG Frank: Social facilitation, affiliation, and dominance in the social life of spotted hyenas. In: Annals of the New York Academy of Sciences 807 (1997), pp. 175-84. PDF
- ↑ Wolfgang Goymann, Marion L. East and Heribert Hofer: Androgens and the Role of Female “Hyperaggressiveness” in Spotted Hyenas ( Crocuta crocuta ) . In: Hormones and Behavior, Volume 39 (2001), pp. 83-92.
- ↑ Holekamp & Kolowski (2009), p. 245.
- ↑ a b c Crocuta crocuta in the IUCN Red List of Threatened Species . Retrieved January 25, 2010.
- ↑ Pokines, JT, Kerbis Peterhans, JC: Spotted hyena (Crocuta crocuta) den use and taphonomy in the Masai Mara National Reserve, Kenya. In: Journal of Archaeological Science 34 (2007): pp. 1914-1931
- ↑ Mills, MGL, Hofer, H .: Status Survey and Conservation Action Plan . (1998) ( Memento of the original from April 21, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Kruuk p. 223
- ↑ a b Holekamp & Kolowski (2009), p. 255.
- ^ OP Höner, B. Wachter, ML East, WJ Streich, K. Wilhelm: Female mate-choice drives the evolution of male-biased dispersal in a social mammal . In: Nature . tape 448 , no. 7155 , p. 798-801 , doi : 10.1038 / nature06040 ( nature.com ).
- ↑ Eve Davidian, Alexandre Courtiol, Bettina Wachter, Heribert Hofer, Oliver P. Höner: Why do some males choose to breed at home when most other males disperse? In: Science Advances . tape 2 , no. 3 , March 1, 2016, ISSN 2375-2548 , p. e1501236 , doi : 10.1126 / sciadv.1501236 , PMID 27034982 , PMC 4803491 (free full text) - ( sciencemag.org [accessed October 20, 2016]).
- ↑ Holekamp & Kolowski (2009), p. 240.
- ↑ a b c Colin Vullioud, Eve Davidian, Bettina Wachter, François Rousset, Alexandre Courtiol, Oliver P. Höner: Social support drives female dominance in the spotted hyaena . In: Nature Ecology & Evolution . tape 3 , no. 1 , January 2019, ISSN 2397-334X , p. 71–76 , doi : 10.1038 / s41559-018-0718-9 ( nature.com [accessed July 26, 2019]).
- ↑ Jennifer E. Smith, Russel C. Van Horn, Katherine S. Powning, Alison R. Cole, Katharine E. Graham, Sandra K. Memenis, Kay E. Holekamp: Evolutionary forces favoring intragroup coalitions among spotted hyenas and other animals . In: Behavioral Ecology . tape 21 , no. 2 , March 1, 2010, ISSN 1045-2249 , p. 284–303 , doi : 10.1093 / beheco / arp181 ( oup.com [accessed August 2, 2019]).
- ^ Marion L. East, Oliver P. Höner, Bettina Wachter, Kerstin Wilhelm, Terry Burke: Maternal effects on offspring social status in spotted hyenas . In: Behavioral Ecology . tape 20 , no. 3 , May 1, 2009, ISSN 1045-2249 , p. 478-483 , doi : 10.1093 / beheco / arp020 ( oxfordjournals.org [accessed October 20, 2016]).
- ^ A b Heribert Hofer, Marion L. East: Behavioral processes and costs of co-existence in female spotted hyenas: a life history perspective . In: Evolutionary Ecology . tape 17 , no. 4 , ISSN 0269-7653 , p. 315–331 , doi : 10.1023 / A: 1027352517231 ( springer.com [accessed October 20, 2016]).
- ↑ Oliver P. Höner, Bettina Wachter, Heribert Hofer, Kerstin Wilhelm, Dagmar Thierer: The fitness of dispersing spotted hyaena sons is influenced by maternal social status . In: Nature Communications . tape 1 , no. 5 , August 24, 2010, ISSN 2041-1723 , p. 1-7 , doi : 10.1038 / ncomms1059 , PMID 20975715 , PMC 2964455 (free full text) - ( nature.com [accessed October 20, 2016]).
- ^ Marion L. East, Heribert Hofer: Loud calling in a female-dominated mammalian society: II. Behavioral contexts and functions of whooping of spotted hyaenas, Crocuta crocuta . In: Animal Behavior . tape 42 , no. 4 , October 1, 1991, p. 651-669 , doi : 10.1016 / S0003-3472 (05) 80247-7 ( sciencedirect.com [accessed October 20, 2016]).
- ↑ a b c d Holekamp & Kolowski (2009), p. 254.
- ↑ a b Spotted Hyena: Diet and Foraging at Hyaena Specialist Group ( Memento of the original dated February 4, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed September 12, 2009.
- ↑ a b Oliver P. Höner, Bettina Wachter, Marion L. East, Heribert Hofer: The response of spotted hyaenas to long-term changes in prey populations: functional response and interspecific kleptoparasitism . In: Journal of Animal Ecology . tape 71 , no. 2 , March 1, 2002, ISSN 1365-2656 , p. 236–246 , doi : 10.1046 / j.1365-2656.2002.00596.x ( wiley.com [accessed October 20, 2016]).
- ↑ a b Holekamp & Kolowski (2009), p. 256.
- ^ A b Jürgen W. Frembgen: The Magicality of the Hyena: Beliefs and Practices in West and South Asia. ( Memento of the original from June 25, 2008 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: Asian Folklore Studies, 57 (1998), pp. 331-344. PDF ( Memento of the original from June 25, 2008 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Nowak (1999), p. 793.
- ^ Alfred Brehm : Brehm's Thierleben: Die Säugethiere 1 in the Gutenberg-DE project ( archive version )
- ↑ Stephen E. Glickman: The spotted hyena from Aristotle to the Lion King: reputation is everything - In the Company of Animals. , Social Research, Fall, 1995 ( memento of July 12, 2012 in the web archive archive.today ), accessed on September 14, 2009.
- ↑ Historia Animalium VI, 32; engl. Online edition , accessed January 18, 2016.
- ↑ Holekamp & Kolowski (2009), p. 250.
- ↑ Holekamp & Kolowski (2009), p. 251.
- ↑ a b Michael V. Westbury, Stefanie Hartmann, Axel Barlow, Michaela Preick, Bogdan Ridush, Doris Nagel, Thomas Rathgeber, Reinhard Ziegler, Gennady Baryshnikov, Guilian Sheng, Arne Ludwig, Ingrid Wiesel, Love Dalen, Faysal Bibi, Lars Werdelin, Rasmus Heller, Michael Hofreiter: Hyena paleogenomes reveal a complex evolutionary history of cross-continental gene flow between spotted and cave hyena. Science Advances 6 (11), 2020, p. Eaay0456, doi: 10.1126 / sciadv.aay0456
- ↑ Klaus-Peter Koepfli, Susan M. Jenks, Eduardo Eizirik, Tannaz Zahirpour, Blaire Van Valkenburgh and Robert K. Wayne: Molecular systematics of the Hyaenidae: Relationships of a relictual lineage resolved by a molecular supermatrix. In: Molecular Phylogenetics and Evolution 38 (2006) 603-620.
- ↑ Martin Dockner: Comparison of Crocuta crocuta crocuta and Crocuta crocuta spelaea through Computed Tomography. ( Memento of the original from May 22, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 1.4 MB) Department of Paleontology, University of Vienna, accessed on September 14, 2009.
- ^ Rohland, N., Pollack, J., L., Nagel, D., Beauval, C., Airvaux, J., Pääbo, S., Hofreiter, M. (2005): The Population History of Extant and Extinct Hyenas . Molecular Biology and Evolution 22 (12): pp. 2435-2443 doi : 10.1093 / molbev / msi244 .
Web links
- Spotted Hyaena ( Crocuta crocuta ) on the Hyaena Specialist Group
- Hyena Project - Ngorongoro Crater
- Crocuta crocuta in the endangered Red List species the IUCN 2009. Posted by: Honer, O., Holekamp, KE & Mills, G., 2008. Accessed January 25 of 2010.
