Department of Primatology
Max Planck Institute for Evolutionary Anthropology
Deutscher Platz 6
phone.: +49 (341) 3550 - 200
fax: +49 (341) 3550 - 299
Several thousand chimpanzees inhabit a remote forest area in the northern Democratic Republic of the Congo
With great ape populations in fast decline, it is crucial to obtain a global picture of their distribution and abundance, in order to channel and direct conservation activities to where they are most needed. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and the University of Amsterdam in The Netherlands conducted hundreds of kilometers of chimpanzee surveys at multiple sites in the Central Uele region of northern Democratic Republic of the Congo and discovered a large, continuous population of Eastern chimpanzees (Pan troglodytes schweinfurthii). The population in the remote Bili-Gangu forest was surveyed in 2005 with line transects and again in 2012, and appears to have remained stable. The total area surveyed, which encompasses about 50,000 square kilometers, is home to several thousands of chimpanzees and, according to the researchers, should be considered a priority site for conservation of the eastern subspecies.
Chimpanzees keep track of other group members’ bonding partners and use this knowledge in conflict situations
To know who your opponents’ family and friends are can be of advantage in a conflict situation. Humans make predictions about other people’s social relationships frequently. Whether other animals also have the cognitive skills to track their group mates’ social relationships across time and beyond close kin has so far not been known. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig have now conducted playback experiments with wild-living chimpanzees from Budongo Forest in Uganda. Two hours after a subject attacked or had been attacked by an opponent, the researchers broadcast the recording of a third individual’s aggressive barks from a speaker near the subject. If the call provider was their opponent’s close buddy or kin, subjects looked longer and moved away more often from barks than if the call provider was not a bond partner. This shows that chimpanzees know who their group mates’ kin or non-kin bond partners are and that their behavior may have an impact on them.
New documentation about the Taï chimpanzees
Please do not miss watching this new documentation (in German or French) about the Taï chimpanzees, Dr. Tobias Deschner and Adnan at ARTE: 16.01.2014 at 19:00 pm or 23.01. at 7:45 am
Chimpanzees who share their food with others have higher levels of the hormone oxytocin in their urine
The ability to form long-term cooperative relationships between unrelated individuals is one of the main reasons for human’s extraordinary biological success, yet little is known about its evolution and mechanisms. The hormone oxytocin, however, plays a role in it. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, measured the urinary oxytocin levels in wild chimpanzees after food sharing and found them to be elevated in both donor and receiver compared to social feeding events without sharing. Furthermore, oxytocin levels were higher after food sharing than after grooming, another cooperative behaviour, suggesting that food sharing might play a more important role in promoting social bonding. By using the same neurobiological mechanisms, which evolved within the context of building and strengthening the mother-offspring bond during lactation, food sharing might even act as a trigger for cooperative relationships in related and unrelated adult chimpanzees.
Contrary to humans and chimpanzees bonobos retain elevated thyroid hormones well into adulthood
Despite the fact that chimpanzees and bonobos share similar starting conditions at birth they develop different behavioural patterns later in life. These differences might be caused by different hormone levels. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and the Royal Zoological Society of Antwerp in Belgium have analyzed thyroid hormones from urine samples of zoo-living chimpanzees and bonobos. They discovered that bonobos retain elevated thyroid hormone concentrations well into adulthood, whereas in humans and chimpanzees thyroid hormone concentrations decline after puberty. The late decline of thyroid hormones in bonobos might have consequences on their behaviour and might also indicate a delayed development of their mental capacities.
Searching for bountiful fruit crops in the rain forest, chimpanzees remember past feeding experiences
Where do you go when the fruits in your favourite food tree are gone and you don’t know which other tree has produced new fruit yet? An international team of researchers, led by Karline Janmaat from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, studied whether chimpanzees aim their travel to particular rainforest trees to check for fruit and how they increase their chances of discovering bountiful fruit crops. The scientists found that chimpanzees use long-term memory of the size and location of fruit trees and remember feeding experiences from previous seasons using a memory window which can be two months to three years ago.
In bonobos, attractive females are more likely to win conflicts against males
Female social dominance over males is rare among mammal species. Bonobos, one of our closest living relatives, are known for females holding relatively high social statuses when compared to males; though this is puzzling as the males are often bigger and stronger than the females. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have now analyzed the dominance relations between male and female wild bonobos and took particular interest in the high social status ranking of some females. The result: It is not female alliances that help females win conflicts. The context of the conflict does not seem to be relevant for its outcome either. Instead, the attractiveness of females plays an important role. If females display sexually attractive attributes, including sexual swellings, they win conflicts with males more easily, with the males behaving in a less aggressive way.
Researchers found that adult wild chimpanzees have developed a certain immunity against malaria parasites
Wild great apes are widely infected with malaria parasites. Yet, nothing is known about the biology of these infections in the wild. Using faecal samples collected from wild chimpanzees, an international team of researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig and the Robert Koch Institute in Berlin has now investigated the effect of the animals’ age on malaria parasite detection rates. The data show a strong association between age and malaria parasite positivity, with significantly lower detection rates in adult chimpanzees. This suggests that, as in humans, individuals reaching adulthood have mounted an effective protective immunity against malaria parasites.
Chimpanzees use Botanical Skills to Discover Fruit
Fruit-eating animals are known to use their spatial memory to relocate fruit, yet, it is unclear how they manage to find fruit in the first place. Researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have now investigated which strategies chimpanzees in the Taï National Park in Côte d’Ivoire, West Africa, use in order to find fruit in the rain forest. The result: Chimpanzees know that trees of certain species produce fruit simultaneously and use this botanical knowledge during their daily search for fruit.
Max Planck researchers find stable isotope evidence of meat eating and hunting specialization in adult male chimpanzees
Observations of hunting and meat eating in our closest living relatives, chimpanzees, suggest that regular inclusion of meat in the diet is not a characteristic unique to Homo. Wild chimpanzees are known to consume vertebrate meat, but its actual dietary contribution is often unknown. Constraints on continual direct observation throughout the entire hunting season mean that behavioural observations are limited in their ability to accurately quantify meat consumption. An interdisciplinary team of researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, has now compared stable isotope data of wild chimpanzee hair keratin and bone collagen with behavioural observations and found that, in chimpanzees, hunting and meat-eating is male-dominated. These new results support previous behavioural observations of chimpanzees in Taï National Park, Côte d’Ivoire.
Taï chimpanzees featured in Hollywood movie
Oscar, Freddy and Isha are the stars of the new Disneynature film CHIMPANZEE which opens in France on February 20th, 2013 and in Germany on May 09th, 2013! This marks the first time ever that a feature film was shot entirely in the wild, and uses footage from the chimpanzees living in the Taï National Park, Côte d’Ivoire and in the Ngogo area of the Kibale National Park, Uganda. The 3 main stars, Oscar, Freddy and Isha, belong to the chimpanzee groups that Max Planck Director Christophe Boesch and his team have studied for the last 33 years in Côte d’Ivoire.
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