̽��ֱ�� of Cambridge - Kathelijne Koops

Young male chimpanzees play more than females with objects, but do not become better tool users

fpjl2 — Wed, 07 Oct 2015 18:03:34 +0000

New research shows a difference between the sexes in immature chimpanzees when it comes to preparing for adulthood by practising object manipulation – considered ‘preparation’ for tool use in later life.

Researchers studying the difference in tool use between our closest living relatives, chimpanzees and bonobos, found that immature bonobos have low rates of object manipulation, in keeping with previous work showing bonobos use few tools and none in foraging.

Chimpanzees, however, are the most diverse tool-users among non-human primates, and the researchers found high rates of a wide range of object manipulation among the young chimpanzees they studied.

While in adult wild chimpanzees it is females that are more avid and competent tool users, in juvenile chimpanzees the researchers conversely found it was the young males that spent more time manipulating objects, seemingly in preparation for adult tool use.

“In numerous mammalian species, sex differences in immatures foreshadow sex differences in the behaviour of adults, a phenomenon known as ‘preparation’,” said Dr Kathelijne Koops, who conducted the work at the ̽��ֱ�� of Cambridge’s Division of Biological Anthropology, as well as at the Anthropological Institute and Museum at Zurich ̽��ֱ��.

Much of the time young male chimpanzees spent manipulating objects was dominated by ‘play’: with no apparent immediate goal, and often associated with a ‘play face’ – a relaxed expression of laughing or covering of upper teeth.

̽��ֱ��sex bias for object manipulation the researchers found in juvenile chimpanzees is also found in human children. “ ̽��ֱ��finding that in immature chimpanzees, like humans, object-oriented play is biased towards males may reflect a shared evolutionary history for this trait dating back to our last common ancestor,” write the researchers from Cambridge, Zurich and Kyoto, who studied communities of wild chimpanzees and bonobos in Uganda and Congo for several months, cataloguing not just all tool use, but all object manipulation.

Immature females, on the other hand, showed lower rates of object manipulation, especially in play, but displayed a much greater diversity of manipulation types than males – such as biting, breaking or carrying objects – rather than the play-based repetition seen in the object manipulation of immature males.

This seems to prepare the females better for future tool use. In an earlier study at Gombe (Tanzania), immature female chimpanzees were also observed to pay closer attention to their mothers using tools and became proficient tool users at an earlier age than males.

“Immature females seem to focus their attention on relevant tool use related tasks and thus learn quicker, whereas males seem to do more undirected exploration in play,” write the researchers.

They say they believe the findings show that not all object manipulation in juvenile chimpanzees is preparation for tool use, and the different types of object manipulation need to be considered.

̽��ֱ��researchers say that the apparent similarity between human children and young chimpanzees in the observed male bias in object manipulation, and manipulation during play in particular, may suggest that object play functions as motor skill practice for male-specific behaviours such as dominance displays, which sometimes involve the aimed throwing of objects, rather than purely to develop tool use skills.

However, the researchers also point out that further work is needed to disentangle possible functions of object manipulation during development.

“We found that young chimpanzees showed higher rates and, importantly, more diverse types of object manipulation than bonobos. Despite being so closely related on the evolutionary tree, as well as to us, these species differ hugely in the way they use tools, and clues about the origins of human tool mastery could lie in the gulf between chimpanzees and bonobos,” Koops said.

“We found that male chimpanzees showed higher object manipulation rates than females, but their object manipulation was dominated by play. Young female chimpanzees showed much more diverse object manipulation types,” she said.

“We suggest that the observed male bias in young chimpanzees may reflect motor skill practice for male-specific behaviours, such as dominance displays, rather than for tool use skills. It seems that not all object manipulation in immatures prepares for subsistence tool use. It is important to take the types of manipulation into consideration.”

̽��ֱ��researchers also found that in chimpanzees, but not bonobos, the types of objects manipulated became more tool-like as the apes age. “As young chimpanzees get older they switch to manipulating predominantly sticks, which in this community is the tool type used by adults to harvest army ants,” Koops explained.

This practice of ant ‘dipping’, when chimpanzees lure streams of insects onto a stick, then scoop them up by running a hand along the stick and into the mouth, provides a quick source of protein.

Koops added: “Given the close evolutionary relationship between chimpanzees, bonobos and humans, insights into species and sex differences in ‘preparation’ for tool use between chimpanzees and bonobos can help us shed light on the functions of the highly debated gender differences among children.”

̽��ֱ��research is published today in the journal PLOS ONE.

Research into differences between chimpanzees and bonobos in ‘preparation’ for tool use reveals intriguing sex bias in object manipulation in young chimpanzees – one that is partly mirrored in human children.

We found that male chimpanzees showed higher object manipulation rates than females, but their object manipulation was dominated by play

Kathelijne Koops

Kat Koops

Young chimpanzee playing with branches.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Tool use is 'innate' in chimpanzees but not bonobos, their closest evolutionary relative

fpjl2 — Tue, 16 Jun 2015 08:22:36 +0000

Chimpanzees and bonobos are the two closest living relatives of the human species - the ultimate tool-using ape. Yet, despite being so closely related on the evolutionary tree, wild chimpanzees and bonobos differ hugely in the way they use tools.

Chimpanzees show the most diverse range of tool use outside of humans. For example, chimpanzees use sticks to 'fish' for ants and termites, stones to crack nuts, as well as tools for grooming and communication. Bonobos rarely use tools and never to forage for food.

̽��ֱ��question of 'what makes a tool user?' is a key one in human evolution, says researcher Dr Kathelijne Koops, and the origins of human tool mastery could lie in the gulf between tool use in chimpanzees and bonobos.

Is it to do with the environment the apes live in and the surrounding opportunities for tool use? Or perhaps the opportunities to learn from other apes through social contact? Or something deep-rooted. Something intrinsic.

Koops, in collaboration with colleagues from Kyoto ̽��ֱ��, conducted painstaking research tracking communities of wild chimpanzees and bonobos in Uganda and Congo for months, cataloguing not just all tool use, but also all potential for tool use in terms of the different environments and social time spent.

They also investigated the innate propensity for object manipulation in young apes, regardless of whether said object was deployed as a 'tool' - the first wild inter-species comparison of its kind.

̽��ֱ��researchers found that environmental opportunities did not explain the difference in tool use. From nut trees to ant nests, stones to shrubs, the bonobos had access to as many tools and promising foraging opportunities in their stomping ground as the chimpanzees.

Nor did social opportunities. In fact, young bonobos spent more time with their mothers, and had more individuals in close proximity for more time whilst feeding than young chimpanzees. Young bonobos also had more social partners than young chimpanzees.

However, immature chimpanzees manipulated and played a lot more with objects than bonobos, and played with objects on their own. This was a difference already visible in very young individuals, says Koops. In fact, she says this is the first evidence for a species difference in the innate predisposition for tool use in our closest evolutionary cousins.

"Chimpanzees are object-oriented, in a way that bonobos are not," said Koops, who conducted the work at Cambridge ̽��ֱ��'s Division of Biological Anthropology and at Zurich ̽��ֱ��'s Anthropological Institute and Museum.

"Given the close evolutionary relationship between these two species and humans, insights into the tool use difference between chimpanzees and bonobos can help us identify the conditions that drove the evolution of human technology.

"Our findings suggest that an innate predisposition, or intrinsic motivation, to manipulate objects was likely also selected for in the hominin lineage and played a key role in the evolution of technology in our own lineage," she said.

̽��ֱ��research is published today in the journal Scientific Reports.

Inset image: Young Bonobos Engaged in Social Play. Credit: Kathelijne Koops

First evidence for a species difference in the innate predisposition for tool use in our closest evolutionary cousins could provide insight into how humans became the ultimate tool-using ape.

Insights into the tool use difference between chimpanzees and bonobos can help us identify the conditions that drove the evolution of human technology

Kathelijne Koops

A Young Chimpanzee Playing with Twigs

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Opportunity, and not necessity, is the mother of invention

amb206 — Wed, 12 Nov 2014 09:00:00 +0000

Whether you're a human being or an orangutan, tools can be a big help in getting what you need to survive. However, a review of current research into the use of tools by non-human primates suggests that ecological opportunity, rather than necessity, is the main driver behind primates such as chimpanzees picking up a stone to crack open nuts.

An opinion piece by Dr Kathelijne Koops of the ̽��ֱ�� of Cambridge and others, published today (12 November 2014) in Biology Letters, challenges the assumption that necessity is the mother of invention. She and her colleagues argue that research into tool use by primates should look at the opportunities for tool use provided by the local environment.

Koops and colleagues reviewed studies on tool use among the three habitual tool-using primates – chimpanzees, orangutans and bearded capuchins.

Chimpanzees use a variety of tools in a range of contexts, including stones to crack open nuts, and sticks to harvest aggressive army ants. Orangutans also use stick tools to prey on insects, as well as to extract seeds from fruits. Bearded capuchin monkeys living in savannah-like environments also use a variety of tools, including stones to crack open nuts and sticks to dig for tubers.

̽��ֱ��researchers’ review of the published literature, including their own studies, revealed that, against expectations, tool use did not increase in times when food was scarce. Instead, tool use appears to be determined by ecological opportunity with calorie-rich but hard-to-reach foodstuffs, such as nuts and honey, appearing to act as an incentive for an ingenious use of materials.

“By ecological opportunity, we mean the likelihood of encountering tool materials and resources whose exploitation requires the use of tools. We showed that these ecological opportunities influence the occurrence of tool use. ̽��ֱ��resources extracted using tools, such as nuts and honey, are among the richest in primate habitats. Hence, extraction pays off, and not just during times of food scarcity,” said Koops.

Tool use – and transmission of tool-making and tool-using skills between individuals – is seen as an important marker in the development of culture. “Given our close genetic links to our primate cousins, their tool use may provide valuable insights into how humans developed their extraordinary material culture and technology,” said Koops.

It has been argued that culture is present among wild primates because simple ecological and genetic differences alone cannot account for the variation in behaviour – such as tool use – observed across populations of the same species.

Koops and co-researchers argue that this ‘method of exclusion’ may present a misleading picture when applied to the material aspects of culture.

“ ̽��ֱ��local environment may exert a powerful influence on culture and may, in fact, be critical for understanding the occurrence and distribution of material culture. In forests with plenty of nut trees, we are more likely to find chimpanzees cracking nuts, which is the textbook example of chimpanzee material culture,” said Koops.

“Our study suggests that published research on primate cultures, which depend on the ‘method of exclusion’, may well underestimate the cultural repertoires of primates in the wild, perhaps by a wide margin. We propose a model in which the environment is explicitly recognised as a possible influence on material culture.”

̽��ֱ��opinion piece ‘Ecological conditions influence primate cultures’ is published by Biology Letters. ̽��ֱ��authors are Kathelijne Koops ( ̽��ֱ�� of Cambridge, Archaeology & Anthropology & ̽��ֱ�� of Zurich, Anthropological Institute and Museum), Elisabetta Visalberghi (CNR, Institute of Cognitive Sciences) and Carel van Schaik ( ̽��ֱ�� of Zurich, Anthropological Institute & Museum).

Inset image: a chimpanzee uses a stick to extract ants (Kathelijne Koops)

When food is scarce, tool use among non-human primates does not increase. This counterintuitive finding leads researchers to suggest that the driving force behind tool use is ecological opportunity – and that the environment shapes development of culture.

Ecological opportunities influence the occurrence of tool use. ̽��ֱ��resources extracted using tools, such as nuts and honey, are among the richest in primate habitats. Hence, extraction pays off...

Kathelijine Koops

A chimpanzee uses a stone to crack a nut

̽��ֱ��text in this work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page. For image rights, please see the credits associated with each individual image.

Yes

Chimpanzees have favourite ‘tool set’ for hunting staple food of army ants

fpjl2 — Thu, 16 Oct 2014 09:49:00 +0000

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.

̽��ֱ��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.

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

“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. ̽��ֱ��average ‘dipping’ tool length across the study was 64 centimetres, but dipping tools got up to 76 cm.

̽��ֱ��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.”

̽��ֱ��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”.

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).

“This study is part of a big ongoing research project. ̽��ֱ��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). 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.

Inset image: Fanwaa the chimpanzee. Credit: Kathelijne Koops

New research shows that chimpanzees search for the right tools from a key plant species when preparing to ‘ant dip’ - a crafty technique enabling them to feast on army ants without getting bitten. ̽��ֱ��study shows that army ants are not a poor substitute for preferred foods, but a staple part of chimpanzee diets.

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

Kathelijne Koops

K Koops YT

Kathelijne Koops

Chimp eating army ants using an 'ant-dipping' tool

Yes