Arquivo da tag: Chimpanzés

New evidence of cultural diversification between neighboring chimpanzee communities (University of Cambridge)

22-JUL-2015

VIDEO: CHIMPANZEES USE TOOLS TO FEED ON ARMY ANTS. CREDIT: KATHELIJNE KOOPS

For centuries it has been thought that culture is what distinguishes humans from other animals, but over the past decade this idea has been repeatedly called into question. Cultural variation has been identified in a growing number of species in recent years, ranging from primates to cetaceans. Chimpanzees, our closest living relatives, show the most diverse cultures aside from humans, most notably, in their use of a wide variety of tools.

The method traditionally used to establish the presence of culture in wild animals compares behavioural variation across populations and excludes all behavioural patterns that can be explained by genetic or environmental differences across sites. Nevertheless, it is impossible to conclusively rule out the influence of genetics and environmental conditions in geographically distant populations.

To circumnavigate this problem, researchers, led by Dr. Kathelijne Koops, took a new approach. “We compared neighbouring chimpanzee groups living under similar environmental conditions, which allows for the investigation of fine scale cultural differences, whilst keeping genetics constant,” said Koops.

She and colleagues from Kyoto University and Freie Universität Berlin compared the length of tools used for ‘ant-dipping’ between two neighbouring chimpanzee communities, M-group and S-group, in the Kalinzu Forest, Uganda. Dipping for army ants is one of the hallmark examples of culture in chimpanzees and involves the use of a stick to extract the highly aggressive army ants from their underground nests.

Previous research has shown that ant-dipping tool length varied across chimpanzee study sites in relation to the army ant species (Dorylus spp.) that were present. So Koops compared the availability of the different species of army ants and the length of dipping tools used in the two adjacent chimpanzee communities.

The researchers found that M-group tools were significantly longer than S-group tools, despite identical army ant species availability. Considering the lack of ecological differences between the two communities, the tool length difference was concluded to be cultural. “Our findings highlight how cultural knowledge can generate small-scale cultural diversification in neighbouring groups,” said Koops.

“Given the close evolutionary relationship between chimpanzees and humans, insights into what drives cultural diversification in our closest living relatives will in turn shed light on how cultural differences emerge and are maintained between adjacent groups in human societies,” said Koops, who conducted the work at Cambridge University’s Division of Biological Anthropology and at Zurich University’s Anthropological Institute and Museum.

The research is published today in the Nature journal Scientific Reports.

Anúncios

Chimpanzés caçadores dão pistas sobre os primeiros humanos (El País)

Primatas que usam lanças podem fornecer indícios sobre origem das sociedades humanas

 12 MAY 2015 – 18:14 BRT

Um velho chimpanzé bebe água em um lago, em Fongoli, no Senegal. / FRANS LANTING

Na quente savana senegalesa se encontra o único grupo de chimpanzés que usa lanças para caçar animais com os quais se alimenta. Um ou outro grupo de chimpanzés foi visto portando ferramentas para a captura de pequenos mamíferos, mas esses, na comunidade de Fongoli, caçam regularmente usando ramos afiados. Esse modo de conseguir alimento é um uso cultural consolidado para esse grupo de chimpanzés.

Além dessa inovação tecnológica, em Fongoli ocorre também uma novidade social que os distingue dos demais chimpanzés estudados na África: há mais tolerância, maior paridade dos sexos na caça e os machos mais corpulentos não passam com tanta frequência por cima dos interesses dos demais, valendo-se de sua força. Para os pesquisadores que vêm observando esse comportamento há uma década esses usos poderiam, além disso, oferecer pistas sobre a evolução dos ancestrais humanos.

“São a única população não humana conhecida que caça vertebrados com ferramentas de forma sistemática, por isso constituem uma fonte importante para a hipótese sobre o comportamento dos primeiros hominídeos, com base na analogia”, explicam os pesquisadores do estudo no qual formularam suas conclusões depois de dez anos observando as caçadas de Fongoli. Esse grupo, liderado pela antropóloga Jill Pruetz, considera que esses animais são um bom exemplo do que pode ser a origem dos primeiros primatas eretos sobre duas patas.

Os machos mais fortes dessa comunidade respeitam as fêmeas na caça

Na sociedade Fongoli as fêmeas realizam exatamente a metade das caçadas com lança. Graças à inovação tecnológica que representa a conversão de galhos em pequenas lanças com as quais se ajudam para caçar galagos – pequenos macacos muito comuns nesse entorno –, as fêmeas conseguem certa independência alimentar. Na comunidade de Gombe, que durante muitos anos foi estudada por Jane Goodall, os machos arcam com cerca de 90% do total das presas; em Fongoli, somente 70%. Além disso, em outros grupos de chimpanzés os machos mais fortes roubam uma de cada quatro presas caçadas pelas fêmeas (sem ferramentas): em Fongoli, apenas 5%.

Uma fêmea de chimpanzé apanha e examina um galho que usará para capturar sua presa. / J. PRUETZ

“Em Fongoli, quando uma fêmea ou um macho de baixo escalão captura uma presa, permitem que ele fique com ela e a coma. Em outros lugares, o macho alfa ou outro macho dominante costuma tomar-lhe a presa. Assim, as fêmeas obtêm pouco benefício da caça, se outro chimpanzé lhe tira sua presa”, afirma Pruetz. Ou seja, o respeito dos machos de Fongoli pelas presas obtidas por suas companheiras serviria de incentivo para que elas se decidam a ir à caça com mais frequência do que as de outras comunidades. Durante esses anos de observação, praticamente todos os chimpanzés do grupo – cerca de 30 indivíduos – caçaram com ferramentas,

O clima seco faz com que os macacos mais acessíveis em Fongoli sejam os pequenos galagos, e não os colobos vermelhos – os preferidos dos chimpanzés em outros lugares da África –, que são maiores e difíceis de capturar por outros que não sejam os machos mais rápidos e corpulentos. Quase todos os episódios de caça com lanças observados (três centenas) se deram nos meses úmidos, nos quais outras fontes de alimento são escassas.

A savana senegalesa, com poucas árvores, é um ecossistema que tem uma importante semelhança com o cenário em que evoluíram os ancestrais humanos. Ao contrário de outras comunidades africanas, os chimpanzés de Fongoli passam a maior parte do tempo no chão, e não entre os galhos. A excepcional forma de caça de Fongoli leva os pesquisadores a sugerir em seu estudo que os primeiros hominídeos provavelmente intensificaram o uso de ferramentas tecnológicas para superar as pressões ambientais, e que eram até mesmo “suficientemente sofisticados a ponto de aperfeiçoar ferramentas de caça”.

“Sabemos que o entorno tem um impacto importante no comportamento dos chimpanzés”, afirma o primatólogo Joseph Call, do Instituto Max Planck. “A distribuição das árvores determina o tipo de caça: onde a vegetação é mais frondosa, a caçada é mais cooperativa em relação a outros entornos nos quais é mais fácil seguir a presa, e eles são mais individualistas”, assinala Call.

No entanto, Call põe em dúvida que essas práticas de Fongoli possam ser consideradas caçadas com lança propriamente ditas, já que para ele lembram mais a captura de formigas e cupins usando palitos, algo mais comum entre os primatas. “A definição de caça que os pesquisadores estabelecem em seu estudo não se distingue muito do que fazem colocando um raminho em um orifício para conseguir insetos para comer”, diz Call. Os chimpanzés de Fongoli cutucam com paus os galagos quando eles se escondem em cavidades das árvores para forçá-los a sair e, uma vez fora, lhes arrancam a cabeça com uma mordida. “É algo que fica entre uma coisa e a outra”, argumenta.

Esses antropólogos acreditam que o achado permite pensar que os primeiros hominídeos eretos também usavam lanças

Pruetz responde a esse tipo de crítica dizendo que se trata de uma estratégia para evitar que o macaco os morda ou escape, uma situação muito diferente daquela de colocar um galho em um orifício para capturar bichos. Se for o mesmo, argumentam Pruetz e seus colegas, a pergunta é “por que os chimpanzés de outros grupos não caçam mais”.

Além do caso particular, nem sequer está encerrado o debate sobre se os chimpanzés devem ser considerados modelos do que foram os ancestrais humanos. “Temos de levar em conta que o bonobo não faz nada disso e é tão próximo de nós como o chimpanzé”, defende Call. “Pegamos o chimpanzé por que nos cai bem para assinalar determinadas influências comuns. É preciso ter muito cuidado e não pesquisar a espécie dependendo do que queiramos encontrar”, propõe.

Chimps joining new troop learn its ‘words’: study (Reuters)

BY SHARON BEGLEY

NEW YORK, Thu Feb 5, 2015 1:03pm EST

(Reuters) – Just as Bostonians moving to Tokyo ditch “grapefruit” and adopt “pamplemousse,” so chimps joining a new troop change their calls to match those of their new troop, scientists reported on Thursday in the journal Current Biology.

The discovery represents the first evidence that animals besides humans can replace the vocal sounds their native group uses for specific objects – in the chimps’ case, apples – with those of their new community.

One expert on chimp vocalizations, Bill Hopkins of Yerkes National Primate Research Center in Atlanta, who was not involved in the study, questioned some of its methodology, such as how the scientists elicited and recorded the chimps’ calls, but called it “interesting work.”

Chimps have specific grunts, barks, hoots and other vocalizations for particular foods, for predators and for requests such as “look at me,” which members of their troop understand.

Earlier studies had shown that these primates, humans’ closest living relatives, can learn totally new calls in research settings through intensive training. And a 2012 study led by Yerkes’ Hopkins showed that young chimps are able to pick up sounds meaning “human, pay attention to me,” from their mothers.

But no previous research had shown that chimps can replace a call they had used for years with one used by another troop. Instead, primatologists had thought that sounds referring to objects in the environment were learned at a young age and essentially permanent, with any variations reflecting nuances such as how excited the animal is about, say, a banana.

In the new research, scientists studied adult chimpanzees that in 2010 had been moved from a safari park in the Netherlands to Scotland’s Edinburgh Zoo, to live with nine other adults in a huge new enclosure.

It took three years, and the formation of strong social bonds among the animals, but the grunt that the seven Dutch chimps used for “apple” (a favorite food) changed from a high-pitched eow-eow-eow to the lower-pitched udh-udh-udh used by the six Scots, said co-author Simon Townsend of the University of Zurich. The change was apparent even to non-chimp-speakers (scientists).

“We showed that, through social learning, the chimps could change their vocalizations,” Townsend said in an interview. That suggests human language isn’t unique in using socially-learned sounds to signify objects.

Unanswered is what motivated the Dutch chimps to sound more like the Scots: to be better understood, or to fit in by adopting the reining patois?

(Reporting by Sharon Begley; Editing by Nick Zieminski)

Chimpanzees in Uganda forced to steal from maize plantations to survive – video (The Guardian)

Source: PLOS One/Wild Chimpanzees on the Edge: Nocturnal Activities in Croplands

Video

The great apes are facing new challenges to coexist with humans. Their home, the Kibale national park, is increasingly being encroached as agricultural fields keep getting closer to the forest. For chimpanzees inhabiting the patch next to the fields, borders are risky areas. But the animals have devised a way to avoid confrontation with humans – they conduct nocturnal raids. This footage shows chimpanzees taking maize from a plantation inside the park

Chimpanzees have favorite ‘tool set’ for hunting staple food of army ants (University of Cambridge)

15-Oct-2014

Fred Lewsey

This video shows a chimpanzee who has constructed a tool with which to investigate a camera (Nimba mountains, Guinea). 

West African chimpanzees will search far and wide to find Alchornea hirtella, a spindly shrub whose straight shoots provide the ideal tools to hunt aggressive army ants in an ingenious fashion, new research shows.

The plant provides the animals with two different types of tool, a thicker shoot for ‘digging’ and a more slender tool for ‘dipping’.

On locating an army ant colony, chimpanzees will dig into the nest with the first tool – aggravating the insects. They then dip the second tool into the nest, causing the angry ants to swarm up it. Once the slender shoot is covered in ants, the chimpanzees pull it out and wipe their fingers along it: scooping up the ants until they have a substantial handful that goes straight into the mouth in one deft motion.

This technique – ‘ant dipping’ – was previously believed to be a last resort for the hungry apes, only exploited when the animal’s preferred food of fruit couldn’t be found. But the latest study, based on over ten years of data, shows that, in fact, army ants are a staple in the chimpanzee diet – eaten all year round regardless of available sources of fruit. Ants may be an important source of essential nutrients not available in the typical diet, say researchers, as well as a potential source of protein and fats.

The new research, published today in the American Journal of Primatology, was led by Dr Kathelijne Koops from the University of Cambridge’s Division of Biological Anthropology and Junior Research Fellow of Homerton College.

This video shows a male chimpanzee looking on at a female who is using an ant-dipping tool (Kalinzu Forest, Uganda).

“Ant dipping is a remarkable feat of problem-solving on the part of chimpanzees,” said Koops. “If they tried to gather ants from the ground with their hands, they would end up horribly bitten with very little to show for it. But by using a tool set, preying on these social insects may prove as nutritionally lucrative as hunting a small mammal – a solid chunk of protein.”

Koops points out that if Alchornea hirtella is nowhere to be found, chimps will fashion tools from other plants – but seemingly only after an exhaustive search for their preferred tool provider.

Previous research has shown that chimpanzees will actually select longer tools for faster, more aggressive types of army ants. The average ‘dipping’ tool length across the study was 64 centimetres, but dipping tools got up to 76 cm.

The question for Koops is one of animal culture: how do chimpanzees acquire knowledge of such sophisticated techniques?

“Scientists have been working on ruling out simple environmental and genetic explanations for group differences in behaviours, such as tool use, and the evidence is pointing strongly towards it being cultural,” said Koops. “They probably learn tool use behaviours from their mother and others in the group when they are young.”

The research for the ant-dipping study – which took place in Guinea’s Nimba mountains – proved challenging, as the chimpanzees were not habituated to people – so the team acted almost as archaeologists, studying ‘exploited’ ants nests to measure abandoned tool sets and “sifting through faeces for ants heads”.

IMAGE: This image shows a chimpanzee using an ant-dipping tool.

To further study these illusive creatures, Koops set up cameras to take extensive video footage of the chimpanzees and their tool use. In doing so, she managed to capture a chimpanzee who has constructed a tool with which to investigate the camera itself – prodding it curiously and then sniffing the end of the tool (VIDEO 1).

“This study is part of a big ongoing research project. The next stages will involve looking at social opportunities to learn: how much time do youngsters spend within arm’s length of other individuals; how much time do they spend close to their mother; as well as innate predispositions to explore and engage with objects,” said Koops.

A video clip from the Kalinzu Forest in Uganda, where Koops is currently conducting comparative studies on East African chimpanzees, captures a male chimpanzee seemingly looking on enviously at a female who has managed to construct a much better dipping tool than his own and is feasting heartily as a consequence (VIDEO 2). Koops suggests this kind of observing of other individuals may lead to learning within a chimpanzee community.

“By studying our closest living relatives we gain a window into the evolutionary past which allows us to shed light on the origins of human technology and material culture,” added Koops.

A link to the paper can be found here: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1098-2345/earlyview

Chimp social network shows how new ideas catch on (New Scientist)

19:00 30 September 2014 by Catherine Brahic

Three years ago, an adult chimpanzee called Nick dipped a piece of moss into a watering hole in Uganda’s Budongo Forest. Watched by a female, Nambi, he lifted the moss to his mouth and squeezed the water out. Nambi copied him and, over the next six days, moss sponging began to spread through the community. A chimp trend was born.

Until that day in November 2011, chimps had only been seen to copy actions in controlled experimentsMovie Camera, and social learning had never been directly observed in the wild.

To prove that Nambi and the seven other chimps who started using moss sponges didn’t just come up with the idea independently, Catherine Hobaiter of the University of St Andrews, UK, and her colleagues used their own innovation: a statistical analysis of the community’s social network. They were able to track how moss-sponging spread and calculated that once a chimp had seen another use a moss sponge, it was 15 times more likely to do so itself.

A decade ago it was believed that only humans have the capacity to imitate, says Frans de Waal of Emory University in Atlanta, Georgia. “The present study is the first on apes to show by means of networking analysis that habits travel along paths of close relationships,” he says, adding that a similar idea was shown not long ago for humpback whale hunting techniques.

Caught in the act

Copying may seem like the easiest thing to us, but not all animals are able. Chimps at the Gombe Stream reserve in Tanzania can copy each other using twigs to fish out termites, but the baboons that watch them haven’t picked up the trick. “They don’t get it,” says Andrew Whiten of the University of St Andrews.

Whiten previously listed 39 behaviours that were found only in some communities of chimps, suggesting these were picked up from other group members rather than being innate behaviours. Since then, more have been added, but they still number in the dozens, not the thousands.

Given how rarely chimps pick up trends, it’s exciting that someone was on hand to watch it happen in this latest study, says Whiten.

Ultimately, he says, our ability to both invent and copy meant our ancestors could exploit a cognitive niche. “They began hunting large game by doing it the brainy way.” Imitation, it turns out, is not just the sincerest form of flattery, it’s also a smart thing to do.

Journal reference: PLoS Biology, DOI: 10.1371/journal.pbio.1001960

Nature of war: Chimps inherently violent; Study disproves theory that ‘chimpanzee wars’ are sparked by human influence (Science Daily)

Date: September 17, 2014

Source: Lincoln Park Zoo

Summary: Of all of the world’s species, humans and chimpanzees are some of the only species to coordinate attacks on their own members. Since Jane Goodall introduced lethal inter-community killings, primatologists have debated the concept of warfare in this genus. New research from an international coalition of ape researchers has shed new light on the subject, suggesting that human encroachment and interference is not, as previous researchers have claimed, an influential predictor of chimp-on-chimp aggression.


The Ngogo males have just killed a male from a neighboring group. After the male is dead, one of the Ngogo males leaps on the body of the dead animal. Credit: Image courtesy of John Mitani 

Of all of the world’s species, humans and chimpanzees are some of the only to engage in coordinated attacks on other members of their same species. Jane Goodall was among the first to introduce the occurrence of lethal inter-community killings and since then primatologists and anthropologists have long debated the concept of warfare in this genus. Research theories have pointed to increased gains and benefits of killing off competitors and opening up increased access to key resources such as food or mates. In contrast, others have argued that warfare is a result of human impact on chimpanzees, such as habitat destruction or food provisioning, rather than adaptive strategies.

New research from an international coalition of ape researchers, published September 18 in the journalNature, has shed new light on the subject, suggesting that human encroachment and interference is not, as previous researchers have claimed, an influential predictor of chimp-on-chimp aggression.

The study began as a response to a growing number of commentators claiming that chimpanzee violence was caused by human impacts. “This is an important question to get right. If we are using chimpanzees as a model for understanding human violence, we need to know what really causes chimpanzees to be violent,” said University of Minnesota researcher Michael L. Wilson, lead author on the study.

“Humans have long impacted African tropical forests and chimpanzees, and one of the long-standing questions is if human disturbance is an underlying factor causing the lethal aggression observed,” explained co-author David Morgan, PhD, research fellow with the Lester E Fisher Center for the Study and Conservation of Apes at Lincoln Park Zoo in Chicago. Morgan has studied chimpanzees deep in the forests of Republic of Congo for 14 years. “A key take-away from this research is that human influence does not spur increased aggression within or between chimpanzee communities.”

A team of 30 ape researchers assembled extensive data sets spanning five decades of research gathered from 18 chimpanzee communities experiencing varying degrees of human influence. In all, data included pattern analysis of 152 killings by chimpanzees. The key findings indicate that a majority of violent attackers and victims of attack are male chimpanzees, and the information is consistent with the theory that these acts of violence are driven by adaptive fitness benefits rather than human impacts.

“Wild chimpanzee communities are often divided into two broad categories depending on whether they exist in pristine or human disturbed environments,” explained Morgan. “In reality, however, human disturbance can occur along a continuum and study sites included in this investigation spanned the spectrum. We found human impact did not predict the rate of killing among communities.

“The more we learn about chimpanzee aggression and factors that trigger lethal attacks among chimpanzees, the more prepared park managers and government officials will be in addressing and mitigating risks to populations particularly with changing land use by humans in chimpanzee habitat,” explained Morgan.

Journal Reference:

  1. Michael L. Wilson, Christophe Boesch, Barbara Fruth, Takeshi Furuichi, Ian C. Gilby, Chie Hashimoto, Catherine L. Hobaiter, Gottfried Hohmann, Noriko Itoh, Kathelijne Koops, Julia N. Lloyd, Tetsuro Matsuzawa, John C. Mitani, Deus C. Mjungu, David Morgan, Martin N. Muller, Roger Mundry, Michio Nakamura, Jill Pruetz, Anne E. Pusey, Julia Riedel, Crickette Sanz, Anne M. Schel, Nicole Simmons, Michel Waller, David P. Watts, Frances White, Roman M. Wittig, Klaus Zuberbühler, Richard W. Wrangham. Lethal aggression in Pan is better explained by adaptive strategies than human impacts. Nature, 2014; 513 (7518): 414 DOI: 10.1038/nature13727

Huge chimpanzee population thriving in remote Congo forest (The Guardian)

Scientists believe the group is one of the last chimp ‘mega-cultures’, sharing a unique set of customs and behaviour

theguardian.com, Friday 7 February 2014 11.53 GMT

A mother chimp passing her tool-use expertise to her young

In one of the most dangerous regions of the planet, against all odds, a huge yet mysterious population of chimpanzees appears to be thriving – for now. Harboured by the remote and pristine forests in the north of the Democratic Republic of Congo (DRC) and on the border of the Central African Republic, the chimps were completely unknown until recently – apart from the local legends of giant apes that ate lions and howled at the moon.

But researchers who trekked thousands of kilometres through uncharted territory and dodged armed poachers and rogue militia, now believe the group are one of the last thriving chimp “mega-cultures”.

“This is one of the few places left on Earth with a huge continuous population of chimps,” says Cleve Hicks, a primatologist based at the Max Planck Institute in Leipzig, Germany, who says the group is probably the largest in Africa. “We estimate many thousands of individuals, perhaps tens of thousands.” A unique set of customs and behaviour is shared by the apes across a vast area of 50,000 sq km, revealing how they live naturally.

The unusually large chimps of the Bili-Uele forest have been seen feasting on leopard and build ground nests far more often than other chimps, as well as having a unique taste for giant African snails, whose shells they appear to pound open on rocks or logs. Motion-activated video cameras left in the forest for eight months also recorded gangs of males patrolling their territory and mothers showing their young how to use tools to eat swarming insects – although the footage did not confirm the lunar howls.

Gangs of males patrolling their territory

The camera traps also revealed an extraordinary range of other forest dwellers, including forest elephantsolive baboonsspotted hyena as well as red river and giant forest hogscrested guinea fowl and aardvark. “We saw incredible amounts of wildlife on our camera traps, but we did not catch a single film of a human,” says Hicks. “It remains one of the last untouched wildernesses in Africa.”

One camera even recorded its own destruction as it came under attack from a leopard, but all two dozen cameras were nearly lost when poachers invaded the area and burned the researchers’ camp. Only a swift two-day rescue mission retrieved the footage.

Forest elephants

Hick’s team first identified the existence of the Bili chimps in 2007 but their new survey, published this week in the journal Biological Conservation, reveals a vast, thriving mega-culture. Elsewhere in Africa, human damage has fragmented the continent’s chimp population from many millions to just a few hundred thousand over the last century.

However, while the chimp numbers have apparently remained stable, the numbers of forest elephants have crashed by half due to poaching. The slaughter, to feed the highly lucrative illegal ivory trade, mirrors the bloody picture across central Africa, where two-thirds of all forest elephants have been killed in the last decade. “We found the burned skulls of a mother and baby skull at a poachers camp,” says Hicks.

Footage of elephant skulls, a sign poachers are venturing deeper into forests to hunt elephants

“The area is at great risk of being opened up,” says John Hart, one of the team and who has spent decades in DRC at the Lukuru Wildlife Research Foundation. The team’s work was interrupted previously by gunmen protecting illegal gold mining operations in nearby areas but the security situation is getting worse, Hart told the Guardian. Speaking from the town of Kisangani, on the eve of returning to the forest, he said: “The Lord’s Resistance Army are moving through the area as we speak. Also refugees from the Central African Republic (CAR) war and armed brigands from the CAR’s Seleka and opposition groups are establishing bases in the region.”

The researchers fear that these increasing incursions into the virgin forest will draw in more hunters seeking to feed the enormous bushmeat trade in the Congo basin, that targets chimps and other animals. “Theincredible bushmeat trade we discovered [in the southern part of the forest in 2010] was totally without precedent.” Hart says, with an estimated 440 chimps being killed a year. “But with the availability of bushmeat declining elsewhere, commercial bushmeat hunters are going further and further into the forest.”

The chimps are an endangered species and fully protected in DRC law. “But it is only a law on paper,” says Hicks, who identifies both official security forces and militia as the source of much of the danger, as well as endemic corruption. “I think the military are giving guns to the poachers.” He says the forest and the chimp mega-culture it contains are currently completely unprotected.

Congo_WEB

The prime minister, David Cameron, and Prince William are due to host the highest level global summit to date on combating the $19bn-a-year illegal wildlife trade in London next Thursday. Delegates from more than 50 nations, including all African countries, will focus on the poaching crisis facing elephants and other species, which is not only driving many towards extinction but is strongly linked to international organised crimeand the poverty of many vulnerable communities. The aim is to deliver an unprecedented political commitment, along with an action plan and funding pledges, and Hicks says the Bili-Uele forest is in need of urgent help.

“It is one of the last great expanses of pristine African wilderness,” he says. “Elephants have already taken a major hit and unless we can muster the resolve to protect this precious area, we are at risk of losing it forever. At the very minimum need 20 wildlife guards who are able to sweep through the forest and set up roadblocks to stop the poachers and other hunters.”

Hart agrees: “It is a very significant opportunity to preserve a whole ecosystem of chimpanzees: elsewhere on this continent this opportunity just does not exist.”

• You can view more camera trap videos from the Bili forest here.

Chimps Can Use Gestures to Communicate in Hunt for Food (Science Daily)

Jan. 17, 2014 — Remember the children’s game “warmer/colder,” where one person uses those words to guide the other person to a hidden toy or treat? Well, it turns out that chimpanzees can play, too.

Chimpanzee. Remember the children’s game “warmer/colder,” where one person uses those words to guide the other person to a hidden toy or treat? Well, it turns out that chimpanzees can play, too. (Credit: © maradt / Fotolia)

Researchers at Georgia State University’s Language Research Center examined how two language-trained chimpanzees communicated with a human experimenter to find food. Their results are the most compelling evidence to date that primates can use gestures to coordinate actions in pursuit of a specific goal.

The team devised a task that demanded coordination among the chimps and a human to find a piece of food that had been hidden in a large outdoor area. The human experimenter did not know where the food was hidden, and the chimpanzees used gestures such as pointing to guide the experimenter to the food.

Dr. Charles Menzel, a senior research scientist at the Language Research Center, said the design of the experiment with the “chimpanzee-as-director” created new ways to study the primate.

“It allows the chimpanzees to communicate information in the manner of their choosing, but also requires them to initiate and to persist in communication,” Menzel said. “The chimpanzees used gestures to recruit the assistance of an otherwise uninformed person and to direct the person to hidden objects 10 or more meters away. Because of the openness of this paradigm, the findings illustrate the high level of intentionality chimpanzees are capable of, including their use of directional gestures. This study adds to our understanding of how well chimpanzees can remember and communicate about their environment.”

The paper, “Chimpanzees Modify Intentional Gestures to Co-ordinate a Search for Hidden Food,” has been published inNature Communications. Academics at the University of Chester and University of Stirling collaborated on the research project.

Dr. Anna Roberts of the University of Chester said the findings are important.

“The use of gestures to coordinate joint activities such as finding food may have been an important building block in the evolution of language,” she said.

Dr. Sarah-Jane Vick of the University of Stirling added, “Previous findings in both wild and captive chimpanzees have indicated flexibility in their gestural production, but the more complex coordination task used here demonstrates the considerable cognitive abilities that underpin chimpanzee communication.”

Dr. Sam Roberts, also from the University of Chester, pointed out the analogy to childhood games.

“This flexible use of pointing, taking into account both the location of the food and the actions of the experimenter, has not been observed in chimpanzees before,” Roberts said.

The project was supported by The Leakey Foundation, the Wenner-Gren Foundation, National Institutes of Health, the Economic and Social Research Council, the British Academy, the Carnegie Trust for the Universities of Scotland and the University of Stirling.

Journal Reference:

  1. Anna Ilona Roberts, Sarah-Jane Vick, Sam George Bradley Roberts, Charles R. Menzel. Chimpanzees modify intentional gestures to coordinate a search for hidden foodNature Communications, 2014; 5 DOI:10.1038/ncomms4088

The Way to a Chimpanzee’s Heart Is Through Its Stomach (Science Daily)

Jan. 16, 2014 — 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.

After hunting, chimpanzees share the meat of a red colobus monkey amongst them. (Credit: © Roman M. Wittig / Taï Chimpanzee Project)

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 behavior, 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.

Humans and a few other social mammals form cooperative relationships between unrelated adults that can last for several months or years. According to recent studies the hormone oxytocin, which facilitates bonding between mother and offspring, likely plays a role in promoting these relationships. In chimpanzees, for instance, increased urinary oxytocin levels are linked to grooming between bonding partners, whether or not they are genetically related to each other.

To examine the ways in which oxytocin is associated with food sharing, Roman Wittig and colleagues of the Max Planck Institute for Evolutionary Anthropology in Leipzig have collected and analyzed 79 urine samples from 26 wild chimpanzees from Budongo Forest in Uganda within one hour after the chimpanzees either shared food or socially fed without sharing. The result: A chimpanzee’s urine contained significantly higher levels of oxytocin after sharing food with another group member than just after feeding socially regardless whether the animal was the donor or the receiver of the food. “Increased urinary oxytocin levels were independent of whether subjects gave or received food, shared with kin or non-kin, shared with an established bond partner or not, or shared meat or other food types,” says Roman Wittig.

In addition, the researchers found that the oxytocin levels associated with food sharing were higher than those associated with grooming, indicating that the rarer food sharing has a stronger bonding effect than the more frequently occurring grooming. “Food sharing may be a key behavior for social bonding in chimpanzees,” says Wittig. “As it benefits receivers and donors equally, it might even act as a trigger and predictor of cooperative relationships.”

The researchers further suggest that food sharing likely activates neurobiological mechanisms that originally evolved to support mother-infant bonding during lactation. “Initially, this mechanism may have evolved to maintain bonds between mother and child beyond the age of weaning,” says Wittig. “It may then have been hitch-hiked and is now also promoting bond formation and maintenance in non-kin cooperative relationships.”

The Latin roots of the word companion (‘com = with’ and ‘panis = bread’) may indicate a similar mechanism to build companionship in humans. Whether human urinary oxytocin levels also increase after sharing a meal with others will be a subject for future studies.

Journal Reference:

  1. R. M. Wittig, C. Crockford, T. Deschner, K. E. Langergraber, T. E. Ziegler, K. Zuberbuhler. Food sharing is linked to urinary oxytocin levels and bonding in related and unrelated wild chimpanzeesProceedings of the Royal Society B: Biological Sciences, 2014; 281 (1778): 20133096 DOI: 10.1098/rspb.2013.3096

Chimpanzees Are Rational, Not Conformists, Researchers Find (Science Daily)

Dec. 13, 2013 — Chimpanzees are sensitive to social influences but they maintain their own strategy to solve a problem rather than conform to what the majority of group members are doing. However, chimpanzees do change their strategy when they can obtain greater rewards, MPI researchers found. The study was published in PLOS ONE on November 28, 2013.

Chimpanzees are sensitive to social influences but they maintain their own strategy to solve a problem rather than conform to what the majority of group members are doing. (Credit: Image courtesy of Max-Planck-Gesellschaft)

Chimpanzees are known for their curious nature. They show a rich palette of learning behaviour, both individually and socially. But they are also rather hesitant to abandon their personal preferences, even when that familiar behaviour becomes extremely ineffective. Under which circumstances would chimpanzees flexibly adjust their behaviour? Edwin van Leeuwen and colleagues from the MPI’s for Psycholinguistics and Evolutionary Anthropology conducted a series of experiments in Germany and Zambia to answer this question.

Wooden balls for peanuts

The researchers studied 16 captive chimpanzees at the Wolfgang Kohler Primate Research Center in Germany (Leipzig) and 12 semi-wild chimpanzees at the Chimfunshi Wildlife Orphanage Trust, a sanctuary that houses more than a hundred chimpanzees under nearly natural conditions in the north-western part of Zambia. Chimpanzees were trained on two different vending machines. A minority of the group was made familiar with one machine and the majority of group members with the other machine. Wooden balls were thrown into their enclosure; the chimpanzees could insert these balls into the machines to receive one peanut for each ball.

Van Leeuwen and his colleagues first aimed to replicate previous research and looked whether the chimpanzees in the minority group would change their behaviour toward using the vending machine that the majority of group members used. However, neither the German nor the Zambian chimpanzees gave up their strategy to join the majority. In the second study, the profitability of the vending machines was changed so that the vending machine that the minority used became more profitable, now spitting out five rewards for every ball inserted. Over time, the majority chimpanzees observed that the minority chimpanzees received more peanuts for the same effort and all but one gradually switched to using this more profitable machine.

Higher rewards

“Where chimpanzees do not readily change their behaviour under majority influences, they do change their behaviour when they can maximise their payoffs,” Van Leeuwen says. “We conclude that chimpanzees may prefer persevering in successful and familiar strategies over adopting the equally effective strategy of the majority, but that chimpanzees find sufficient incentive in changing their behaviour when they can obtain higher rewards somewhere else.” “So, it’s peanuts over popularity” he jokingly adds.

The researchers emphasise that these results may be dependent upon the specific trade-offs that were created by the experimental design and that chimpanzees could act differently under the pressures of life in the wild. Van Leeuwen: “Conformity could still be a process guiding chimpanzees’ behaviour. Chimpanzee females, for instance, disperse to other groups in the wild. For these females, it is of vital importance to integrate into the new group. Conformity to local (foraging) customs might help them to achieve this integration.”

Journal Reference:

  1. Edwin J. C. Van Leeuwen, Katherine A. Cronin, Sebastian Schütte, Josep Call, Daniel B. M. Haun. Chimpanzees (Pan troglodytes) Flexibly Adjust Their Behaviour in Order to Maximize Payoffs, Not to Conform to MajoritiesPLoS ONE, 2013; 8 (11): e80945 DOI:10.1371/journal.pone.0080945

Ativistas exigem direitos legais para chimpanzés (O Globo)

JC e-mail 4868, de 04 de dezembro de 2013

Ano foi marcado por conquistas de símios em tribunais. Agência federal anunciou que pretende aposentar os macacos que pertencem ao governo

Chimpanzés não são pessoas, mas seriam parecidos o suficiente para merecerem alguns direitos humanos. Esta é a reivindicação de um grupo de proteção dos animais que entrou com um pedido de habeas corpus para assegurar os direitos de Tommy, um símio da cidade americana de Gloversville, no estado de Nova York. Seu caso será analisado pelo Tribunal do Condado de Fulton.

Tommy não é o primeiro chimpanzé defendido em tribunais. O Projeto dos Direitos de Animais não Humanos trabalha há anos em estratégias que assegurem um tratamento justo aos animais nos 50 estados americanos, cada qual com sua legislação. A partir delas, o programa quer esboçar o que seria uma lei comum, suficientemente forte para reconhecer aos animais direitos legais, que permitam até que sejam beneficiários de herança.

O líder do projeto, Steven Wise, lembra da história da luta contra a escravidão humana ao explicar sua cruzada pelo direito dos animais. Para ele, os macacos, como os humanos, não podem ser propriedade de ninguém.

A ação judicial em Gloversville é o novo marco de um ano já marcado por polêmicas protagonizadas por chimpanzés.

Uma agência federal já anunciou novas medidas para aposentar alguns símios que são propriedade do governo; outro órgão público propôs classificar todos os chimpanzés como animais ameaçados de extinção. Esta medida prejudicaria experimentos com estes animais, mesmo aqueles realizados em laboratórios particulares.

Ativistas exaltaram suas recentes conquistas, enquanto alguns cientistas condenaram as restrições ao uso dos símios, que exerceram um papel crucial em algumas pesquisas médicas, como no trabalho para o desenvolvimento de uma vacina para a hepatite C.

Até agora, as ações judiciais reivindicavam o bem-estar dos animais, não os seus direitos. Esta semana, no entanto, Wise anunciou sua intenção de que Tommy fosse reconhecido como uma pessoa jurídica, com direito à liberdade. O chimpanzé, segundo Wise, está “mantido em cativeiro dentro de uma jaula no galpão de um estacionamento”.

O documento enviado para o Tribunal de Fulton não pede para que o animal tenha liberdade para circular em Gloversville, tampouco seu envio à África, após uma vida em cativeiro. O condado analisará apenas a remoção do símio de seus donos e a transferência do chimpanzé para um santuário.

O O Projeto dos Direitos de Animais revelou sua intenção de mover ações semelhantes a favor de três outros chimpanzés de Nova York. Dois deles seriam de um centro de pesquisas universitário, usados em um estudo sobre locomoção. O outro pertence a uma ONG.

(O Globo com informações do New York Times)
http://oglobo.globo.com/ciencia/ativistas-exigem-direitos-legais-para-chimpanzes-10959633#ixzz2mVuPNlsF

Lawsuits Could Turn Chimpanzees Into Legal Persons (Science)

2 December 2013 1:00 pm

Property or person? A series of lawsuits could free U.S. chimpanzees from captivity.

© Martin Harvey/Corbis. Property or person? A series of lawsuits could free U.S. chimpanzees from captivity.

This morning, an animal rights group known as the Nonhuman Rights Project (NhRP) filed a lawsuit in a New York Supreme Court in an attempt to get a judge to declare that chimpanzees are legal persons and should be freed from captivity. The suit is the first of three to be filed in three New York counties this week. They target two research chimps at Stony Brook University and two chimps on private property, and are the opening salvo in a coordinated effort to grant “legal personhood” to a variety of animals across the United States.

If NhRP is successful in New York, it could be a significant step toward upending millennia of law defining animals as property and could set off a “chain reaction” that could bleed over to other jurisdictions, says Richard Cupp, a law professor at Pepperdine University in Malibu, California, and a proponent of focusing on animal welfare rather than animal rights. “But if they lose it could be a significant step backward for the movement. They’re playing with fire.”

The litigation has been in the works since 2007, when animal rights attorney Steven Wise founded NhRP, an association of about 60 lawyers, scientists, and policy experts. The group argues that cognitively advanced animals like chimpanzees and dolphins are so self-aware that keeping them in captivity—whether a zoo or research laboratory—is tantamount to slavery. “It’s a terrible torture we inflict on them, and it has to stop,” Wise says. “And all of human law says the way things stop is when courts and legislatures recognize that the being imprisoned is a legal person.”

NhRP spent 5 years researching the best legal strategy—and best jurisdiction—for its first cases. The upshot: a total of three lawsuits to be filed in three New York trial courts this week on behalf of four resident chimpanzees. One, named Tommy, lives in Gloversville in a “used trailer lot … isolated in a cage in a dark shed,” according to an NhRP press release. Another, Kiko, resides in a cage on private property in Niagara Falls, the group says. The final two, Hercules and Leo, are research chimps at Stony Brook University. Wise says that 11 scientists have filed affidavits in support of the group’s claims; most of them, including Jane Goodall, have worked with nonhuman primates.

In each case, NhRP is petitioning judges with a writ of habeas corpus, which allows a person being held captive to have a say in court. In a famous 1772 case, an English judge allowed such a writ for a black slave named James Somerset, tacitly acknowledging that he was a person—not a piece of property—and subsequently freed him. The case helped spark the eventual abolition of slavery in England and the United States. Wise is hoping for something similar for the captive chimps. If his group wins any of the current cases, it will ask that the animals be transferred to a chimpanzee sanctuary in Florida. Any loss, he says, will immediately be appealed.

Regardless of what happens, NhRP is already preparing litigation for other states, and not all of it involves chimpanzees. “Gorillas, orangutans, elephants, whales, dolphins—any animal that has these sorts of cognitive capabilities, we would be comfortable bringing suit on behalf of,” Wise says. Some would be research animals; others would be creatures that simply live in confined spaces, such as zoos and aquariums. “No matter how these first cases turn out, we’re going to move onto other cases, other states, other species of animals,” he says. “We’re going to file as many lawsuits as we can over the next 10 or 20 years.”

Frankie Trull, the president of the National Association for Biomedical Research in Washington, D.C., says her organization will fight any attempts at personhood in the courts. Chimpanzees, she notes, are important models for behavioral research, as well as for developing vaccines against viruses like hepatitis C. “Assigning rights to animals akin to what humans have would be chaotic for the research community.”

Anatomist Susan Larson, who studies the Stony Brook chimpanzees to shed light on the origin of bipedalism in humans, says she is “very shocked and upset” by the lawsuit. She says the chimps live in an indoor enclosure comprised of three rooms—“about the size of an average bedroom”—plus another room where they can climb, hang, and jump from ladders and tree trunks. “Everything I do with these animals I’ve done on myself,” she says. “I understand that animal rights activists don’t want these animals mistreated, but they’re hampering our ability to study them before they become extinct.”

The more immediate threat to Larson’s research isn’t NhRP, however—it is the National Institutes of Health (NIH). In June, NIH announced plans to retire all but 50 of its 360 research chimpanzees and phase out much of the chimp research it supports. The U.S. Fish and Wildlife Service, meanwhile, has recommended that captive chimps be listed as endangered, which would limit any research that isn’t in their best interest. “Soon, the type of work I do will no longer be possible,” Larson says. “They have effectively ended my research program.”

Stephen Ross, the director of the Lester E. Fisher Center for the Study and Conservation of Apes at the Lincoln Park Zoo in Chicago, Illinois, wonders if there’s a compromise. Ross, who has studied chimpanzees for more than 20 years and played a role in crafting NIH’s new policy, advocates ending private ownership of chimps and invasive research. All other chimpanzees, he says, whether located at zoos or universities, should live in large enclosures, with access to the outside, and in group sizes of at least seven individuals. “You don’t need personhood to do that,” he says. “I think we share a common philosophy,” he says of NhRP. “We want to make things better for chimps. We just disagree on how to get there.”

 

A more detailed version of this story will appear in the 6 December issue of Science.

*Clarification, 2 December, 4 p.m.: This item has been updated to reflect Richard Cupp’s position on animal rights.

Chimpanzees Successfully Play the Ultimatum Game: Apes’ Sense of Fairness Confirmed (Science Daily)

Jan. 14, 2013 — Researchers at the Yerkes National Primate Research Center, Emory University, are the first to show chimpanzees possess a sense of fairness that has previously been attributed as uniquely human. Working with colleagues from Georgia State University, the researchers played the Ultimatum Game with the chimpanzees to determine how sensitive the animals are to the reward distribution between two individuals if both need to agree on the outcome.

Researchers have shown that chimpanzees possess a sense of fairness that has previously been attributed as uniquely human. (Credit: © Sunshine Pics / Fotolia)

The researchers say the findings, available in an early online edition of the Proceedings of the National Academy of Sciences (PNAS) available this week, suggest a long evolutionary history of the human aversion to inequity as well as a shared preference for fair outcomes by the common ancestor of humans and apes.

According to first author Darby Proctor, PhD, “We used the Ultimatum Game because it is the gold standard to determine the human sense of fairness. In the game, one individual needs to propose a reward division to another individual and then have that individual accept the proposition before both can obtain the rewards. Humans typically offer generous portions, such as 50 percent of the reward, to their partners, and that’s exactly what we recorded in our study with chimpanzees.”

Co-author Frans de Waal, PhD, adds, “Until our study, the behavioral economics community assumed the Ultimatum Game could not be played with animals or that animals would choose only the most selfish option while playing. We’ve concluded that chimpanzees not only get very close to the human sense of fairness, but the animals may actually have exactly the same preferences as our own species.” For purposes of direct comparison, the study was also conducted separately with human children.

In the study, researchers tested six adult chimpanzees (Pan troglodytes) and 20 human children (ages 2 — 7 years) on a modified Ultimatum Game. One individual chose between two differently colored tokens that, with his or her partner’s cooperation, could be exchanged for rewards (small food rewards for chimpanzees and stickers for children). One token offered equal rewards to both players, whereas the other token favored the individual making the choice at the expense of his or her partner. The chooser then needed to hand the token to the partner, who needed to exchange it with the experimenter for food. This way, both individuals needed to be in agreement.

Both the chimpanzees and the children responded like adult humans typically do. If the partner’s cooperation was required, the chimpanzees and children split the rewards equally. However, with a passive partner, who had no chance to reject the offer, chimpanzees and children chose the selfish option.

Chimpanzees, who are highly cooperative in the wild, likely need to be sensitive to reward distributions in order to reap the benefits of cooperation. Thus, this study opens the door for further explorations into the mechanisms behind this human-like behavior.

For eight decades, the Yerkes National Primate Research Center, Emory University, has been dedicated to conducting essential basic science and translational research to advance scientific understanding and to improve the health and well-being of humans and nonhuman primates. Today, the center, as one of only eight National Institutes of Health-funded national primate research centers, provides leadership, training and resources to foster scientific creativity, collaboration and discoveries. Yerkes-based research is grounded in scientific integrity, expert knowledge, respect for colleagues, an open exchange of ideas and compassionate quality animal care.

Within the fields of microbiology and immunology, neurologic diseases, neuropharmacology, behavioral, cognitive and developmental neuroscience, and psychiatric disorders, the center’s research programs are seeking ways to: develop vaccines for infectious and noninfectious diseases; treat drug addiction; interpret brain activity through imaging; increase understanding of progressive illnesses such as Alzheimer’s and Parkinson’s diseases; unlock the secrets of memory; determine how the interaction between genetics and society shape who we are; and advance knowledge about the evolutionary links between biology and behavior.

Journal Reference:

  1. Darby Proctor, Rebecca A. Williamson, Frans B. M. de Waal, and Sarah F. Brosnan. Chimpanzees play the ultimatum gamePNAS, January 14, 2013 DOI:10.1073/pnas.1220806110

Great apes make sophisticated decisions (Max-Planck-Gesellschaft)

By Daniel Haun
Max-Planck-Gesellschaft

Chimpanzees, orangutans, gorillas and bonobos make more sophisticated decisions than was previously thought. Great apes weigh their chances of success, based on what they know and the likelihood to succeed when guessing, according to a study of MPI researcher Daniel Haun, published on December 21 in the online journal PLoS ONE. The findings may provide insight into human decision-making as well.

The authors of the study, led by Daniel Haun of the Max Planck Institutes for Psycholinguistics (Nijmegen) and Evolutionary Anthropology (Leipzig), investigated the behaviour of all four non-human great ape species. The apes were presented with two banana pieces: a smaller one, which was always reliably in the same place, and a larger one, which was hidden under one of multiple cups, and therefore the riskier choice.

The researchers found that the apes’ choices were regulated by their uncertainty and the probability of success for the risky choice, suggesting sophisticated decision-making. Apes chose the small piece more often when they where uncertain where the large piece was hidden. The lower their chances to guess correctly, the more often they chose the small piece.

Risky choices

The researchers also found that the apes went for the larger piece – and risked getting nothing at all – no less than 50% of the time. This risky decision-making increased to nearly 100% when the size difference between the two banana pieces was largest. While all four species demonstrated sophisticated decision making strategies, chimpanzees and orangutans were overall more likely to make risky choices relative to gorillas and bonobos. The precise reason for this discrepancy remains unknown.

Haun concludes: “Our study adds to the growing evidence that the mental life of the other great apes is much more sophisticated than is often assumed.”