Chimpanzees

This article covers the great ape species. The film of the same name is described under chimpanzees (film) .

Chimpanzees
Bonobo ( Pan paniscus )
Systematics
Partial order : Monkey (anthropoidea) without rank: Old World Monkey (Catarrhini) Superfamily : Human (Hominoidea) Family : Apes (Hominidae) Subfamily : Homininae Genre : Chimpanzees
Scientific name
Pan
Oken , 1816

The chimpanzee ( Pan ) are a genus from the family of the apes (Hominidae). Chimpanzees are the closest living relatives of humans and inhabit central Africa . The genus includes two types : the common chimpanzee ( Pan troglodytes ), which is often just called "chimpanzee", and the bonobo or dwarf chimpanzee ( Pan paniscus ).

Skeleton of a chimpanzee, exhibited in the Wiesbaden Museum

Origin of name

The term “chimpanzee” is derived from the Bantu language Tschiluba . "Kivili-chimpenze" is the local name of the animal and can be translated as "pseudo-human" or "monkey". This designation is first documented for the year 1738.

Pan , the scientific generic name, refers to the goat-footed shepherd god Pan in Greek mythology , other ideas also played a role, according to which the chimpanzees appeared in mythical fashion as hairy, tailed prehistoric humans. The epithet troglodytes (Greek, "cave dwellers") is based on the misconception that the early ancestors of anatomically modern humans ( Homo sapiens ) lived in caves. The classifying epithet paniscus for the bonobo is derived from the Greek Πανίσκος ( paniskos ); it means "little pan" and refers to the ancient Greek custom of setting up miniaturized statues of this deity on fields.

anatomy

Head of a bonobo : Characteristic are the long, often parted head of hair and the dark face with light lips.

Head of a common chimpanzee : The skull is more massive, the face usually lighter than that of the bonobo. Some animals have a white goatee.

Chimpanzees reach a head body length of 64 to 94 centimeters, a tail is missing, as with all great apes . Animals standing upright reach a height of 1 to 1.7 meters. In terms of weight, there is a clear sexual dimorphism : while females weigh around 25 to 50 kilograms, males can weigh 35 to 70 kilograms. The term "dwarf chimpanzee" for the bonobo is misleading in that both species are approximately the same size. However, the bonobo has a more delicate skull and fewer muscular limbs.

The arms of the chimpanzee are longer than the legs, hands and feet end in five fingers or toes, whereby the thumb and big toe can be opposed as with many primates , suitable for grasping branches. Most of the body is covered by a dark brown or black fur.

The head is characterized by the prominent, round ears, the bulges above the eyes and the protruding snout. The face is hairless and colored dark gray or black in the adult animal. The two species differ in the structure of the head in that the face of the common chimpanzee is lighter and the forehead more rounded than that of the bonobo.

The canines of the common chimpanzee are strongly sex-dimorphic (significantly larger in males), but very small in the bonobo. Overall, the incisors are wider and the molars have more rounded cusps than in the gorilla, for example .

The body temperature of healthy chimpanzees - like humans - averages 37 degrees Celsius.

distribution and habitat

Distribution area of ​​the chimpanzees: red represents the home of the bonobo , the other colors the different subspecies of the common chimpanzee

Chimpanzees are native to central Africa. While the common chimpanzee range extends from Senegal across Nigeria and the north and east of the Democratic Republic of the Congo to Uganda and Tanzania , the bonobo is endemic to the central and southern parts of the Democratic Republic of the Congo . The Congo represents the southern limit of distribution for the common chimpanzee, this hardly crossable river also forms the border to the home of the bonobos. The lack of gorillas in their habitat, and thus the non-existence of these powerfully strong feeding competitors, may explain that no aggressive and defensive groups of men are organized among them.

Common chimpanzees are more flexible than other great apes with regard to their habitat and inhabit both rainforests and dry, tree-poor savannas. In contrast, bonobos are distinct rainforest dwellers.

Way of life

Movement and activity times

Leaf nest

Chimpanzees can forage both on the ground and in trees, but most of the time they do so in trees. On the ground they move like gorillas in the ankle gait , which means that they support themselves with their front extremities on the second and third phalanges. In the branches they either climb with all four limbs or move around hanging on the arms ( suspensory ). In general, bonobos are to a greater extent tree dwellers and move suspensively more often than common chimpanzees.

As a rule, chimpanzees are diurnal. When they sleep, they make a leaf nest in the trees, usually building a new nest every night. Chimpanzees and other great apes are considered incapable of swimming and can usually be kept on islands surrounded by moats in zoos; numerous cases of drowned great apes are known. In a lecture in 2011, the sports scientist Renato Bender presented the first evidence of swimming behavior in captive and semi-wild chimpanzees and an orangutan to a specialist audience.

Social behavior

Chimpanzees in the Tacugama Sanctuary, near Freetown

The social structure of the chimpanzees is described as a "fission fusion organization". This means that they live in large groups, which, however, often split up into subgroups. These subgroups are very flexible and often represent only temporary associations. Solitary animals can be found next to pairs as well as separate and mixed-sex groups. The organization of the large groups differs in the two species, however: those of the bonobos have a more matriarchal structure and are often led by a female, in the common chimpanzees the males are dominant, as they also form groups of strict hierarchy among each other. With 6 to 23 animals, the subgroups of bonobos are larger than those of the common chimpanzees (on average 4 to 8 animals), more often mixed-sex and generally more peaceful than those of the common chimpanzees. As with many primates, mutual grooming is an important social component - apart from the hygienic purpose - which also serves to forge alliances and to that extent reflects the group hierarchy.

In a behavioral study, eleven individuals were given the opportunity to obtain fruit with the help of an apparatus, but this was only possible if two or three animals operated the apparatus together or if another animal took away their reward after a successful action. The study found that those willing to cooperate carefully choose their partners, those who were “stolen” complained loudly, dominant monkeys intervened after a “theft” or that the whole group took action against the “thief”.

Territorial behavior

Jane Goodall's observation of the "Chimpanzee War" in Gombe and a study carried out afterwards in Kibale National Park have shown that the males of the common chimpanzee can form "combat units" that regularly patrol the borders of the area they inhabit. Occasionally, they begin to cross the borders and attack the chimpanzees that live there. It can happen that their territory is added to your own. In the course of such confrontations, the killing of adult conspecifics was observed, and infants from neighboring groups were also killed. Occasionally child killing occurs within one's own community and is then not infrequently carried out by the dominant females against low-ranking mothers.

Chimpanzee culture and tool use

According to the current state of primate ethology, chimpanzees are also capable of making special inventions and handing them down . This leads to cultural differences: one and the same problem can be solved by each group in its own way. Some of the related achievements - such as B. Knowledge of Medicinal Plants - can best be explained by the fact that a current generation is drawing on knowledge that was discovered by one of their ancestors arbitrarily far back in the past. In such a case, the current chimpanzee culture is shaped by social learning (copying, 'aping') and not by individual trial and error (“trial and error”). For the scientists, however, it was surprising how quickly some animals found an adequate solution in the face of novel problems, which would explain why even neighboring hordes are sometimes extremely culturally different. These differences can be found in the use of tools as well as in mutual grooming and courtship behavior. This is how traditions arise in animals, in that one member of the group makes a new invention that others also adopt. A special case of tradition is the fact that chimpanzees in Guinea have learned to neutralize the traps of poachers.

The use of tools by the common chimpanzee is well documented . They use pieces of wood or stones as hammers and anvils , sticks as probes or digging tools and chewed leaves as sponges.

Researchers have observed in wild chimpanzees in Uganda for over 14 years that female young animals are stick-carrying more often than their male counterparts. The animals carried sticks with them, took them into their resting nests and played with them like a doll or a young animal. This indicates a gender-specific play behavior in great apes, because females showed this behavior more often than their male counterparts. They stopped as soon as they had young animals of their own, whereas other forms of stick use, such as examining holes containing food, using weapons as aggressive behavior and as toys, did not decrease.  The stick-carrying has no obvious function, but it could serve the "mother playing", which can also be observed more often with human children. Male chimpanzees, on the other hand, increasingly used sticks as weapons.

No tool use has been observed on bonobos in the wild, but it has been observed in animals in human captivity.

nutrition

Young chimpanzee eats a fruit

Chimpanzees are omnivores, but most of them feed on plants. Fruits and nuts are the main part of the diet, besides they also consume leaves, flowers, seeds and other plant material. However, chimpanzees also regularly eat insects and various small mammals (such as bats , small primates, and duikers ). Real hunts for small mammals are known of the common chimpanzee, which are mostly carried out by the males and presumably serve less to cover their food needs than to strengthen their position in the group hierarchy.

Reproduction and Life Expectancy

Reproduction can take place all year round. The cycle duration is 35 to 45 days, the fertility of the female, in contrast to other great apes, is indicated by a significant sexual swelling ( normal swelling ) of the buttocks region. After a gestation period of around 220 to 250 days, the female usually gives birth to a single young. Twins are rare, although probably a little more common than in humans. The birth weight of the young animal is around 1 to 2 kilograms.

In the first few months of life it clings to the mother's stomach, later it rides on her back. The weaning usually takes place around the age of 4 instead of to 5 years, but the young remain afterwards for some time in the mother. Sexual maturity occurs at 7 to 9 years of age, however, due to group behavior, the first reproduction occurs significantly later, in the case of the common chimpanzee around 13 to 16 years of age.

Chimpanzees, like all great apes, are long-lived. Animals in human care usually reach an age of around 50 years, but individual animals such as the chimpanzee Gregoire can also get significantly older. In the wild they can live to be 30 to 40 years old.

Chimpanzees and humans

Research history

Behavioral scientist Jane Goodall's work on the wild common chimpanzees was groundbreaking.

How long chimpanzees have been known to the western world cannot be precisely determined. The Carthaginian navigator Hanno († 440 BC) brought back the skins of three “wild women” from his trip to Africa, probably chimpanzees or gorillas. The first living animals came to Europe in the 17th century, and at the latest since Darwin's and Huxley's works on evolutionary theory , chimpanzees have come into the public eye as close relatives of humans.

In 1960, the paleoanthropologist Louis Leakey commissioned Jane Goodall to research the behavior of chimpanzees in order to be able to draw conclusions about the evolution of behavior in the course of human tribal history . The use of tools , learning behavior, social dynamics and communication skills of these great apes are therefore still the focus of research today, well-known scientists are Frans de Waal , David Premack and Roger Fouts . One of the most sensational observations is the so-called Gombe Chimpanzee War .

Evolutionary genetics

Information on the genetic similarity between humans and the various species of great apes was initially based on research findings on similarities in amino acid sequences of certain important proteins; According to these studies, the bonobos were classified as the most closely related species to humans. Preliminary DNA sequencing of the common chimpanzee in 2005 concluded that humans and chimpanzees differ in approximately 1.23 percent of the base pairs for single nucleotide polymorphisms .

The phenotypically large differences between humans and chimpanzees today are not attributed so much to the small differences in the genetic codes of the two species as to the different gene expression . A comparatively large deviation was discovered with regard to the Y chromosome : More than 30 percent of this u. a. the section in the genome of chimpanzees that determines masculinity has no comparable counterpart in humans. There are also relevant differences in the proteins : around 80 percent of all proteins show differences, but most only in one or - as in the case of the forkhead box protein P2 - two amino acids . In April 2007, the result of detailed was DNA sequencing of the rhesus monkey - genome announced. A comparison of 13,888 genes from chimpanzees, humans and rhesus monkeys showed that 233 chimpanzee genes, but only 154 genes in humans, differ so greatly from the rhesus monkey genes that they code for altered proteins . In conclusion, it was postulated that, in the course of the evolutionary evolution of their species, chimpanzees have moved further from the ancestor on which all three species are based than humans. In fact, in 2012 - after sequencing the gorilla genome - a difference ("mean nucleotide divergences") of 1.37% for humans / chimpanzees and 1.81% for gorillas / chimpanzees, but only 1.75% designated for gorilla / human.

Molecular biological comparisons of the DNA of humans and chimpanzees were also used in combination with hypotheses on the frequency of mutations (“ molecular clock ”) in order to limit the time span during which the evolutionary paths of the two species separated. The published calculations of the various research groups, however, differ considerably from one another. On the basis of fossil finds, C. Owen Lovejoy dated this separation in 2009 to the period about 6 to 5 million years ago. Terry Harrison dated the separation of the chimpanzees from the hominini at the beginning of 2010 to 7.5 million years ago. In 2010, Bernard Wood named the period between 6 and 4 million years as the "most likely", and after a revision of the assumptions about the frequency of mutations, a separation was then calculated again in 2012 8 to 7 million years ago.

threat

Both chimpanzee species are threatened by the ongoing destruction of their habitat. In particular, the range of the common chimpanzee is becoming more and more restricted and is severely fragmented. In Uganda, chimpanzees are also increasingly eaten. The bonobo is restricted to a relatively small area and is therefore endangered. Both types are on the IUCN as endangered ( endangered listings). However, there are no reliable estimates of the population size of either species.

In addition, researchers, poachers and ecotourists can transmit human pathogens to chimpanzees and this has already resulted in the death of chimpanzees.

With the development of immunosuppressive drugs in the early 1960s , transplant physicians attempted to transfer chimpanzee kidneys to humans. In anticipation of mass hunting of wild chimpanzees as organ suppliers, conservationists increasingly took measures to preserve the animals. In this context, Bernhard Grzimek poached chimpanzees kept in captivity for the first time in 1966, namely on the island of Rubondo in Lake Victoria . For reintroduction of chimpanzees occurred subsequently also in Senegal and Gambia .

Patent on genetic material from chimpanzees

As of 2012, the European Patent Office granted the patents EP1456346 and EP1572862 from Intrexon and the patent EP1409646 from Altor BioScience on the genome of chimpanzees. Intrexon holds a number of other patents relating to the genetic makeup of mammals of various orders. The company Altor BioScience has "humanized" the immune system of the chimpanzees by inserting appropriate codes in order to be able to better test drugs with antibodies on them. The company cooperates with Genentech , which belongs to Hoffmann-La Roche .

Legal Capacity for Chimpanzees?

With reference to the Civil Practice Law and Rules of the US state of New York , especially Article 70 ( Habeas Corpus ), an animal welfare organization applied to the court in 2014 to recognize the chimpanzee Tommy as a ( legal ) person and consequently to remove him from "captivity" Liberate private keeping. An appeals chamber of the New York Supreme Court (the Supreme Court) rejected this application on the grounds that according to all previous legal opinion, no animal, but only a person (a "human being") could be called a "person".

In contrast, the “ Great Ape Project ” has existed as an international initiative since the 1990s to demand certain human rights for other primates as well. The project goes back to the 1993 book Human Rights for the Great Apes - The Great Ape Project (original title: The Great Ape Project: Equality Beyond Humanity ), which was published by the philosophers Paola Cavalieri and Peter Singer .

Systematics

Position of the chimpanzee ( Pan ) in the family tree of the apes (Hominidae)

External system

The chimpanzee, together with the orangutans ( Pongo ), the gorillas ( Gorilla ) and the human ( Homo ), the family of great apes (hominids). Humans and chimpanzees are the closest living relatives. In 2005 - based on three teeth discovered in Kenya - a fossil chimpanzee was scientifically described for the first time, the age of which was determined to be just over 500,000 years.

The proposal formulated by some researchers around the year 2000 to assign gorillas and chimpanzees to the genus Homo due to the only minor genetic differences between them and humans was not included in the internationally renowned systematic works in the following years.

Internal system

The genus of chimpanzees is divided into two types , the common chimpanzee ( Pan troglodytes ) and the bonobo or dwarf chimpanzee ( Pan paniscus ). It is estimated that the two species separated between 0.8 and 1.8 million years ago. The two differ not least in terms of the forms of coexistence, insofar as the latter form extremely peaceful, female-dominated communities, while the former form those in which the males organize themselves into strictly hierarchical groups that, under certain circumstances, carry out war-like territorial battles .

Four subspecies can be distinguished within the common chimpanzee: P. t. troglodytes (from Cameroon to the west of the Democratic Republic of the Congo ), P. t. schweinfurthii (in Central Africa , the north of the Democratic Republic of the Congo and neighboring countries), P. t. ellioti (in eastern Nigeria and western Cameroon) and P. t. verus (in western Africa from Senegal to Ghana , possibly to Nigeria). This western subspecies differs so strongly from the other subspecies in the skull structure and also in the DNA sequences that it may represent a species of its own.

The "giant chimpanzee" or "bili chimpanzee", sometimes postulated as a separate species or subspecies, has turned out to be a representative of the eastern subspecies of the common chimpanzee ( P. t. Schweinfurthii ) after DNA studies .

literature

• Thomas Geissmann: Comparative Primatology. Springer, Berlin 2002. ISBN 3-540-43645-6 .
• Ronald M. Nowak: Walker's Mammals of the World . 6th edition. Johns Hopkins University Press, Baltimore 1999, ISBN 0-8018-5789-9 (English).
• Alexandra Tischel: Monkeys like us. What the literature says about our closest relatives. JB Metzler, Stuttgart 2018, ISBN 978-3-476-04598-0

Web links

Commons : Chimpanzees  - Collection of images, videos and audio files

Wiktionary: Chimpanzee  - explanations of meanings, word origins, synonyms, translations

• Website of the Kyoto Primate Research Institute of the University of Kyoto (English)

Individual evidence

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2. ↑ Renato Bender & Nicole Bender: The 'Saci last common ancestor hypothesis' and a first description of swimming ability in common chimpanzees ( Pan troglodytes ). Paper presented at the 23rd Annual Conference of the Human Behavior and Evolution Society, June 29–3. July 2011, Montpellier, France.
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6. ↑ Choice of tools: monkeys also have culture. Mirror online. Article dated May 11, 2012.
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9. ^ Julio Mercader et al .: 4300-year-old chimpanzee sites and the origins of percussive stone technology. In: PNAS. Volume 104, No. 9, 2007, pp. 3043-3048, doi: 10.1073 / pnas.0607909104
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10. ↑ Kahlenberg, Sonya M. and Richard W. Wrangham. 2010. Sexdifferences in object use by young chimpanzees resemble those of children. Current Biology 20 (24): R1067-1068. PDF
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13. ^ Duration of Lactation. On: anthropogeny.org , accessed on January 29, 2017
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16. ↑ Kosmos draft of a physical description of the world by Alexander von Humboldt . JG Cotta, 1847 ( google.de [accessed June 30, 2019]).
17. ^ The Chimpanzee Sequencing and Analysis Consortium: Initial sequence of the chimpanzee genome and comparison with the human genome. In: Nature . Volume 437, 2005, pp. 69-87, doi: 10.1038 / nature04072
18. ↑ Nalini Polavarapu et al .: Characterization and potential functional significance of human-chimpanzee large INDEL variation. In: Mobile DNA. Volume 2, 2011, Article No. 13, doi: 10.1186 / 1759-8753-2-13
19. ↑ Jennifer F. Hughes et al .: Chimpanzee and human Y chromosomes are remarkably divergent in structure and gene content. In: Nature. Volume 463, 2010, pp. 536-539, doi: 10.1038 / nature08700
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21. ^ Rhesus Macaque Genome Sequencing and Analysis Consortium: Evolutionary and Biomedical Insights from the Rhesus Macaque Genome. In: Science . Volume 116, No. 5822, 2007, pp. 222-234, doi: 10.1126 / science.1139247
22. ↑ Margaret A. Bakewell, Peng Shi, Jianzhi Zhang: More genes underwent positive selection in chimpanzee evolution than in human evolution. In: PNAS. Volume 104, 2007, p. 7489, doi: 10.1073 / pnas.0701705104 .
23. ↑ Aylwyn Scally et al .: Insights into hominid evolution from the gorilla genome sequence. In: Nature. Volume 483, 2012, pp. 169–175, (here: p. 170), doi: 10.1038 / nature10842
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25. ↑ Terry Harrison, Apes Among the Tangled Branches of Human Origins. In: Science. Volume 327, 2010, pp. 532–534, doi: 10.1126 / science.1184703 , full text (PDF; 435 kB) ( Memento from October 25, 2012 in the Internet Archive )
    In 2010, another study came to the same conclusion, which included both paleontological as well as molecular biological data were included; see Richard D. Wilkinson et al .: Dating Primate Divergences through an Integrated Analysis of Palaeontological and Molecular Data. In: Systematic Biology. Volume 60, No. 1, 2011, pp. 16–31, doi: 10.1093 / sysbio / syq054 (full text freely accessible)
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27. ↑ Kevin E. Langergraber et al .: Generation times in wild chimpanzees and gorillas suggest earlier divergence times in great ape and human evolution. In: PNAS. Volume 109, No. 39, 2012, pp. 15716–15721, doi: 10.1073 / pnas.1211740109
28. ↑ afrika.info, November 2, 2012
29. ^ Sophie Köndgen et al .: Pandemic Human Viruses Cause Decline of Endangered Great Apes. In: Current Biology. Volume 18, No. 4, 2008, pp. 260-264, doi: 10.1016 / j.cub.2008.01.012
    Max Planck Society of January 24, 2008: Chimpanzee death due to human virus.
30. ↑ Felix Schürmann: Homecoming into Neuland: The first release of chimpanzees and their contexts in postcolonial Tanzania, 1965–1966. In: Research focus "Animal - Human - Society" (Ed.): Diverse interwoven: Interdisciplinary contributions to animal-human relationality. Bielefeld 2017, pp. 275–292.
31. ↑ Judgment 518336 of December 4, 2014 regarding the chimpanzee Tommy (PDF)
32. ↑ Animal ethics: The rights of the apes in Neue Zürcher Zeitung from July 5, 2016
33. ^ Sally McBrearty and Nina G. Jablonski : First fossil chimpanzee. In: Nature. Volume 437, 2005, pp. 105-108, doi: 10.1038 / nature04008 , full text ( Memento from December 20, 2018 in the Internet Archive )
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34. ↑ Elizabeth E. Watson, Simon Easteal, and David Penny, Homo Genus: A Review of the Classification of Humans and the Great Apes. In: Phillip Tobias et al. (Ed.): Humanity from African Naissance to Coming Millennia. Colloquia in Human Biology and Palaeoanthropology. Firenze University Press, Florence 2001, pp. 307–318, ISBN 88-8453-003-2 , full text (PDF; 5.4 MB)
35. ^ Evidence for a Complex Demographic History of Chimpanzees
36. ↑ Emma Young and Adrian Barnett: DNA tests solve mystery of giant apes. In: New Scientist . No. 2558, 2006, online preview