Common chimpanzee ( Pan troglodytes )
|Linnaeus , 1758|
The primates (Primates) or primates are to the superiority of the Euarchontoglires related order within the subclass of higher mammals . Their research is the subject of primatology . The term “monkeys” is sometimes used for this order, but it can be misunderstood as monkeys are only a subgroup. Primates in the two sub-systems of the strepsirrhini (Strepsirrhini) and haplorhini divided (Haplorrhini), the latter also the great apes (hominids), including the human ( Homo sapiens ) include with. The name comes from the Latin primus (the first) and refers to humans as the " crown of creation ".
With the exception of humans , who have achieved worldwide distribution, the ranges of other primates are largely restricted to the tropics and subtropics of America , Africa, and Asia . On the American double continent, its current range extends from southern Mexico to northern Argentina . The species on the Caribbean islands , the Antilles monkey (Xenotrichini), have become extinct, today there are only animals introduced by humans. They are widespread in Africa, with the greatest species density in the regions south of the Sahara . On the island of Madagascar , its own primate fauna (exclusively wet-nosed primates) has developed, the lemurs . In Asia, the ranges of the primates include the Arabian Peninsula (however, the mantled baboon may have been introduced by humans), the Indian subcontinent , the People's Republic of China , Japan, and Southeast Asia . The islands of Sulawesi and Timor form the eastern limit of their occurrence . There is only one wild species in Europe, the Barbary macaque in Gibraltar , but this population is also likely introduced by humans.
Non-human primates are absent in central and northern North America , most of Europe , northern and central parts of Asia, the Australian-oceanic region, and on remote islands and in the polar regions.
Unlike other groups of mammals, primates have not been made settled on a large scale by humans in other regions, apart from the aforementioned robe baboons on the Arabian Peninsula and the Barbary macaques in Gibraltar, this only affects small groups, for example a population of the green monkey that is kept by African slaves was brought to the Caribbean island of Saint Kitts , or a group of rhesus monkeys in Florida .
Although primates are a relatively well-defined mammalian order, there are relatively few traits that are found in all animals of this order and no other mammal. Nevertheless, according to the biologist Robert Martin, nine features of the primate order can be recorded:
- The big toe is opposable (exception: humans) and the hands are suitable for grasping.
- The nails on the hands and feet of most species are flat (no claws ). Primates also have fingerprints .
- The locomotion is dominated by the hind legs, the center of gravity is closer to the hind limbs.
- The olfactory perception is unspecialized and reduced in diurnal primates.
- The visual perception is highly developed. The eyes are large and directed forward ( stereoscopy ).
- The females have small litter sizes. Pregnancy and weaning take longer than other mammals of comparable size.
- The brains are relatively larger than other mammals and have some unique anatomical features.
- The molars are relatively unspecialized and there are a maximum of three; as well as a maximum of two incisors , one canine , and three premolars .
- There are other subtle anatomical peculiarities (useful for systematists), but these are difficult to classify functionally.
The smallest primate species is the Berthe mouse lemur with less than 10 centimeters head length and a maximum weight of 38 g. The largest are the gorillas , which can weigh up to 275 kg . In general, wet-nosed primates with an average weight are 500 g smaller than dry-nosed primates with an average weight of 5 kg. This is also based on the different activity times (see below). Some species have a pronounced sexual dimorphism , whereby the males of some species can be twice as heavy as the females and can also differ in the color of their fur (for example in the baboon ).
Most primates' bodies are covered in fur, which can vary in color from white to gray to brown and black. The palms of the hands and soles of the feet are mostly hairless, in some species the face or the whole head (for example uakaris ). The least hairy is humans .
The difference in name between the two subordinates is the nasal mirror (rhinarium), which in the wet-nosed primates is moist and rich in glands and is reflected in a well-developed sense of smell. The dry-nosed primates, on the other hand, have simple, dry nostrils and their sense of smell is far less well developed.
The oldest fossil primates found had a tooth formula of 2-1-4-3, which means two incisors , one canine , four premolars and three molars per half of the jaw , for a total of 40 teeth. However, the maximum tooth formula of the recent primates is 2-1-3-3, which occurs, for example, in the common Makis and Capuchins . Some species have lost further teeth due to diet, for example the weasel lemurs have no incisors in their upper jaw. The fewest teeth of all living species, at 18, have the finger animals , which have no canines and only one incisor per half of the jaw. The Old World monkeys , including the people , the dental formula 2-1-2-3, ie 32 teeth.
The shape of the molars in particular provides information about nutrition. Predominantly fruit-eating species have rounded, insectivorous species have conspicuously pointed molars. In leaf-eaters, the molars have sharp edges that are used to crush the hard leaves.
Since most primate species are tree dwellers, their limbs are adapted to the way of life. The hind legs are almost always longer and stronger than the front legs (exceptions are the Gibbons and non-human primates ) and bear the larger share of the movement. This is particularly pronounced in jumping primates and humans. In species that move through the branches by hand, the thumb is receded (for example in spider monkeys and colobus monkeys ). Wet-nosed primates have a cleaning or toilet claw on the second toe that is used for grooming. The underside of the hands and feet is hairless and provided with sensitive touch panels.
For many tree-dwelling mammals, a long tail is an important organ of equilibrium and balance, as is the case with most primates. However, the tail can be regressed or absent. With the exception of the human species , which are generally tailless, the length of the tail is not a related feature, since stub tails occur in numerous species regardless of development. Even within one genus, the macaque , there are tailless species (for example the barbary macaque ) and species whose tail is longer than the body (for example the long-tailed macaque ). Only a few species of New World monkeys have developed a prehensile tail (the spotted monkeys and the howler monkeys ). This is hairless on the underside and equipped with sensitive nerve cells.
Way of life
It is believed that the primates evolved from tree-dwelling animals and even today many species are pure tree-dwellers that hardly ever come to the ground. Other species are partly terrestrial (living on the ground), such as baboons and hussar monkeys . Only a few species are pure soil dwellers, including the Jelada and humans . Primates can be found in a wide variety of forest forms, including tropical rainforests , mangrove forests , but also mountain forests up to over 3000 m. Although one of these animals generally ascribed to be afraid of water, there are species that no less than swimming, including the proboscis monkey or Allen's swamp monkey has that even small webbed fingers developed. Cities and villages have also become home to some hemerophilic species (cultural followers), for example the rhesus monkey and the Hanuman langur .
Put simply, wet-nosed primates are mostly nocturnal (exceptions: Indri , Sifakas and Varis ), while dry- nosed primates are mostly diurnal (exceptions: goblin lemurs and night monkeys ). The different times of activity are also reflected in the body structure, so in both subgroups nocturnal animals are on average smaller than diurnal animals. The wet-nosed primates' better sense of smell represents a further adaptation to night-time activity. Comparable to other mammals is the fact that species that mainly feed on leaves take longer rest periods to compensate for the low nutritional value of their food.
Primates use different modes of locomotion, which are reflected in different adaptations in the body and also depend on the habitat. The following forms can be distinguished:
- Four-legged walking in the trees: This form of locomotion mainly uses horizontal branches.
- Vertical climbing and jumping: The vertical trunks are mainly used for this. Springable primates have particularly strong hind limbs.
- Slow climbing: This form has been perfected in particular by the Loris , who climb slowly through the branches, but whose firm grip around the branches can hardly be loosened with force.
- Four-legged walking on the floor: hands and feet are used to move on the floor. The details can differ: while baboons put all three phalanges on the ground, gorillas and chimpanzees lean on the second phalanx (so-called ankle gait ).
- Brachiation : In this method, the animals resonate with the help of their powerful arms through the branches. Swinging can be seen in spider monkeys and orangutans , for example . This method was perfected by the gibbons (brachiation).
- Bipedia : The two-legged, upright gait on the floor is practiced by several species of primates at times; in its pure form, this method only occurs in humans and their ancestors ( hominini ).
In most cases, primates have developed complex social behavior. Pure solitary animals are rare, even in species that predominantly live individually (for example the orangutan ), the territories of males and females overlap, and animals from such overlapping territories are preferred for reproduction. Other species live in longstanding monogamous relationships (for example indri-like or gibbons ). In many cases, however, primates live in groups. These can be either harem or single male groups, where a male gathers numerous females, or mixed groups, in which several sexually mature males and females live together. A ranking is usually established in groups , which is determined by age, relatives, struggles and other factors. Presumably in connection with the increasing brain volume, parental care is relatively sophisticated.
The communication and interaction plays an important role. Quite a few species have a variety of sounds that can be used to mark territory, search for group members, threaten or warn of predators. The jungle concerts of the howler monkeys and the duet songs of the gibbon couples are particularly well known . Humans are the only ones who really use a highly complex sound system ( language ). Postures and grimaces can also represent a form of communication, another important form of interaction is mutual grooming. The sense of smell plays a more important role in the wet-nosed primates; the territory is often marked with scent glands or urine.
In the 20th century, the German psychiatrist Detlev Ploog was particularly concerned with the sociology of primates .
There is considerable variability in diet among primates. The following generalizations can still be made:
- All primates have at least one high protein food and at least one high carbohydrate food. Insects or vegetable gums and fruits are the main sources of protein and carbohydrates in monkeys . Insects and young leaves or fruits are usually the main source of protein and carbohydrates in monkeys and humans .
- Most primates feed on certain foods more than others. Scientists use the terms frugivores , folivores , insectivores and gumnivores to denote species that primarily feed on fruits, leaves, insects and vegetable gum.
- Insectivors are mostly smaller than frugivores, and frugivores are smaller than folivores. This is because smaller animals require relatively more energy than larger ones. They need high quality food readily available, while larger animals are not so restricted as they can afford to eat poor quality food more slowly.
Presumably the ancestors of the primates were insectivores, but the majority of the species are primarily herbivores today. Fruits represent the main component of the diet for many species, they are supplemented by leaves, flowers, tubers, mushrooms, seeds, nuts, tree sap and other parts of the plant. However, many species are omnivores and eat not only vegetable but also animal food, especially insects, spiders, bird eggs and small vertebrates. The genera that occasionally hunt larger mammals ( hares , small primates, young arthropods ) include baboons and chimpanzees .
Primates are one of the few vertebrates that cannot produce the important vitamin C themselves. You must therefore ingest it with your food.
Folivore species have special adaptations: the colobus monkeys have a multi-chambered stomach in which microorganisms break down the cellulose . This concept is similar to that of ruminants or some species of kangaroo . Others, like the howler monkeys or the gorillas , have enlarged colon that serve the same purpose.
Since the food supply for folivors tends to be uniform and predictable in terms of time and space, their action spaces are usually smaller than those of frugivores and insectivors.
In general, primates are characterized by a long gestation period, a long development time for the young and a rather high life expectancy. The young animals are usually carried around by the mother and hold onto her fur as active babies . The strategy of these animals is to invest a lot of time in rearing the young, but the reproductive rate is low. Cat lemurs have the shortest gestation period of around 60 days; most species are between four and seven months. Humans and gorillas have the longest gestation period at around nine months.
In most species, single births predominate, and even in those species that usually have multiple births (including lemurs, galagos and marmosets ), the litter size is rarely more than two or three newborns.
Systematics and tribal history
Within the placenta animals , the primates belong to the euarchontoglires , a hierarchy established on the basis of molecular genetic studies. Their closest relatives are the giant gliders (Dermoptera). The shrews (Scandentia), which in the past were sometimes assigned to primates, show similarities in skull structure and behavior, but these are either general characteristics of mammals or convergent developments, so that they are now placed in their own order, Scandentia. The following diagram shows the assumed development relationships within this superordinate order:
The primates comprise more than 500 species, they are now divided into two suborders, the dry- nosed primates (Haplorrhini) and the wet-nosed primates (Strepsirrhini). The wet-nosed primates are divided into the lemurs (Lemuriformes), which live exclusively on Madagascar , and the Lori-like (Lorisiformes), to which Loris and Galagos belong. In the dry- nosed primates, the Koboldmakis stand in opposition to the other species, which are called monkeys (Anthropoidea or Simiae) and which in turn divide into the New World and Old World monkeys . Earlier, the strepsirrhini and the tarsiers were as prosimians (prosimiae) together (sometimes including the giant slider and the tree shrews); these were contrasted with the "real" monkeys.
|Systematics of the recent primates|
The oldest unequivocally primates attributable Fossil discoveries date from the early Eocene (around 55 million years ago). However, these finds, like those of the dry-nosed primate Teilhardina , already document the division into the two suborders, so the origin of the primates is probably in the Upper Cretaceous period around 80 to 90 million years ago.
There are some finds from the Upper Cretaceous and the Paleocene such as Purgatorius or the Plesiadapiformes , which are sometimes referred to as the earliest known primates. Their position is, however, controversial; many authors see them as a completely separate mammalian order.
The finds from the Eocene are assigned to the Adapiformes and the Omomyidae , a family similar to the Koboldmakis and are known from Africa , Asia , Europe and North America . While primates became extinct in North America in the Oligocene , they continued to evolve on the other continents. Today's primates of America, the New World monkeys , have been fossilized for around 35 million years, the oldest known genus is Perupithecus . Ancestors of most of today's families are known from the Miocene , with the exception of the primates of Madagascar, which is probably due to a poor fossil record. In Europe, the non-human primates - from the family of vervet monkeys (Cercopithecidae) - died out in the Pleistocene . Humans (the genus Homo ) have spread over the entire world in an unprecedented manner in the last 100,000 years, so that today - with the exception of the Antarctic continent , where permanent housing developments are lacking - primates can be found all over the world.
Primates and humans
The following chapters deal with the relationship between humans and other primates, whereby humans themselves are largely ignored.
The earliest known primates in the Mediterranean were the Barbary macaque from North Africa and the Mantled baboon from Egypt. The Carthaginian navigator Hanno († 440 BC) brought back the skins of three “wild women”, probably chimpanzees , from his trip to Africa . Aristotle writes about animals that share both characteristics of humans and properties of the "quadrupeds" and divided them into (human) monkeys "monkey with tail" ( κῆβοι kēboi , probably monkeys or macaques ) and baboons ( κυνοκέφαλοι kynokephaloi ). He attested the baboons to have a dog-like snout and teeth and thus coined the term dog monkey . In the 2nd century AD, Galen of Pergamon dissected Barbary macaques and deduced the human anatomy from it; his research was decisive for medicine up to the 16th century. The ideas of primates in the Middle Ages were overlaid with mythical creatures such as hairy, tailed humans and half-creatures similar to the satyr . Pan , the genus name of the chimpanzees, derived from the goat-footed shepherd god Pan , goes back to such ideas. A live chimpanzee came to Holland for the first time in 1641 and was discovered by the Dutch doctor Nicolaes Tulpius (1593–1674), who was immortalized in Rembrandt's painting The Anatomy of Dr. Tulp became famous, studied and published under the title "Indian Satyr". The English doctor and zoologist Edward Tyson (1650–1708) is considered to be the founder of primatology. In 1699 he found a number of similarities between the "orangutan or Homo sylvestris " - in truth a chimpanzee from Angola - and humans. Carl von Linné created the systematics of animals that are still fundamentally valid today. In the tenth edition of his Systema Naturae (1758) , he divided the primates into four genera: Homo (humans), Simia ( great apes and other apes), Lemur (lemurs and other " lower "monkeys") and Vespertilio (bats) - in earlier editions he had also counted sloths among the primates.
One did not want to fully resign themselves to the classification of humans under the primates, so Johann Friedrich Blumenbach divided this group into the "Bimana" (two-handed, i.e. humans) and "Quadrumana" (four-handed, i.e. non-human primates). This classification is also reflected in the fact that great apes were often depicted with a stick at that time, since walking on bipeds without help was reserved for humans. The theory of evolution was developed in the 19th century and Thomas Henry Huxley's work Evidence as to Man's Place in Nature (1863) consistently involved humans in the evolutionary processes, which was to fuel discussions for decades as to whether humans really descended from apes. The British zoologist St. George Mivart (1827–1900), a conservative Catholic and self-taught, tried on the one hand to refute Darwin's and Huxley's theses, among other things with the assertion that the earth has not existed long enough for the evolutionary processes described, but on the other hand it has been modified he Linnaeus the classification by the bats separated out from the primates and until recently valid classification of lemurs and monkeys performed. Mivart also established a list of characteristics of the primates, in which he listed among other things trained collarbones , a grasping foot with opposite big toe and a free-hanging penis with a scrotum behind .
From the 20th century, the history of research was divided into numerous areas, which can only be reproduced here in brief:
- Paleontology : With the help of fossils an attempt was made to determine the exact ancestry relationships within the primates. Particularly intensive attempts were made tounderstandthe tribal history of humans andto findthe long sought " missing link " to their direct animal ancestors.
- Systematics : With the help of DNA comparisons and other comparative methods, the phylogenetic relationships of the various primate groups were analyzed in more detail. Cladistic systematics were developed thatopposethe earlier “progress prejudice” of the classical systematics . This resulted in two fundamental corrections in the system: The traditional division into monkeys and monkeys was abandoned in favor of grouping into wet-nosed primates and dry- nosed primates . The second change concerns the people , the sooner - perhaps as the last remnant of a traditionally granted special role - in their own family (Hominidae) the apes was compared (Pongidae), today however unequivocally classified as a member of the apes (hominids).
- Behavioral research : Instead of purely external descriptions, the focus was on the behavior of the animals. Behaviors and social forms were analyzed more precisely, and many researchers spent several years near the animals in order to be able to carry out precise field studies. Dian Fossey and Jane Goodall are among the most famous researchers. This area also includes intelligence and learning research. The intelligence and learning behavior of the animals should be determined on thebasis of their ability to solve tasks (e.g. to get a fruit out of a box closed with buckles) orto enter into communication with peopleusing symbol cards or sign language . More recently, primate archeology has also been studyingthe history of the earliest demonstrable material culture in primates, that is, their tool use .
- Conservation biology: In view of the in part drastically declining natural habitats of many species, questions of nature conservation and the establishment of suitable protected areas are becoming more and more burning.
The human likeness in physique and multiple habits have often contributed to mythical beliefs. These habits include morning basking in the sun, which has been interpreted as religious sun worship, the screams and chants, and the presumed marital fidelity of some species.
In different religions, some species have been declared sacred animals . The ancient Egyptian god Thoth was sometimes depicted in the form of a baboon . The Egyptian Book of the Dead tells of the baboons, they sit at the bow of the death barge and the dead can turn to them and ask for justice in the realm of the dead at the judgment of the dead. Baboons therefore enjoyed protection and were even mummified. In India , rhesus monkeys and Hanuman langurs are considered sacred. In the epic Ramayana , monkeys led by Hanuman help Prince Rama to free his wife from the clutches of the demon prince Ravana. The monkey-shaped god Hanuman is one of the most popular gods in Hinduism today . In different regions of the world certain primates enjoyed protection from hunting due to mythical beliefs, for example the Indri in Madagascar . In China , the duet chants of the gibbons were associated with the alleged melancholy of these animals, which is reflected in poems and paintings.
Primates as pets
The earliest evidence of primates as pets comes from Ancient Egypt, where pictures show baboons being led on a leash and playing with children. Ancient China are Gibbons known as pets. Primates have been kept as pets for thousands of years, and this is still common in some places today. Are held mainly apes and smaller species such as squirrel monkeys - known was the chimp Michael Jackson . The problem here is that these animals are rarely bred, but are mostly caught as young animals, which is often associated with the killing of the mother. From the point of view of animal welfare , primates are generally rejected as pets, as species-appropriate keeping is hardly possible and diseases can also be transmitted in both directions.
Primates as farm animals
There are no classic farm animals among the primates. In the field of medical research and the testing of cosmetics, primates are widely used for animal experiments . The best known is probably the rhesus factor , which was discovered in 1940 in rhesus monkeys . In the past, the search for experimental animals has decimated the populations in some cases drastically; today the animals are mostly bred for these purposes. The point and use of animal testing is hotly debated and the discussion about it is extremely controversial.
Another area of application for primates was space travel . The first was "Gordo" in 1958 , a squirrel monkey that was launched into space on a Redstone rocket. More squirrel monkeys, rhesus monkeys and chimpanzees followed in the space programs of the USA , France and the Soviet Union .
In the USA there are projects in which capuchin monkeys are trained to help physically disabled people.
The largest species extinction in the recent past has occurred in Madagascar . The island, which was only settled by humans around 1500 years ago, is home to numerous endemic animal species, including five primate families. At least eight genera and fifteen species have since become extinct there, most likely due to hunting, possibly coupled with climatic changes. The primates that have been exterminated there include primarily larger, ground-living species, including the giant lemurs Megaladapis and the gorilla-sized Archaeoindris as well as the Palaeopropithecinae ("sloth lemurs") and Archaeolemurinae ("baboon lemurs").
From a global perspective, the situation of many primate species is worrying. As primarily forest-dwelling animals, they are drastically exposed to the dangers associated with large-scale deforestation. The distribution areas of many species only make up a fraction of their historical occurrence. The hunt does the rest: reasons for hunting include their meat, which is eaten, and their fur. Added to this is the fact that they devastate plantations and fields, as well as the - largely illegal - search for pets. Mostly the mothers are killed in order to be able to catch adolescent animals. Although the International Union for Conservation of Nature lists no species of primate as extinct in the last 200 years, a number are considered critically endangered. The primates most threatened include the spider monkeys and lion tamarins from South America, the silver gibbon endemic to Java , several snub-nosed species and the Sumatran orangutan .
According to a study published in June 2019, 75% of primate species are declining and 60% are critically endangered. Increasing deforestation is one of the main reasons. Between 2001 and 2015, 47% of the forest area in Southeast Asia was cleared, in South and Central America and South Asia this figure is 26% and in Africa 7% of the forest area disappeared.
Changes in the magnitude and intensity of extreme weather events - including cyclones and droughts - caused by man-made climate change have a negative impact on the global primate population. A study from 2019 shows that 16% of primate taxa are susceptible to cyclones (especially in Madagascar) and 22% to droughts (especially on the Malaysian peninsula, in North Borneo, on Sumatra and in the tropical wet forests of West Africa) .
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