New Chimp&See paper : Highly precise community science annotations of video camera-trapped fauna in challenging environments.

 New Chimp&See paper out in Remote Sensing in Ecology and Conservation: "Highly precise community science annotations of video camera-trapped fauna in challenging environments."  https://zslpublications.onlinelibrary.wiley.com/doi/10.1002/rse2.402

Even though they require more time for annotation as compared to stills, camera trap videos provide valuable acoustic and visual information on species behaviour and can improve identification of individuals. 

Using the Community Science (CS) platform Chimp&See (chimpandsee.org), we found that when comparing classification of 13,531 one-minute video clips done by a professional ecologist to those done by 1,744 Chimp&See community scientists, the overall, annotation precision was between 95.4% and 98.1%. Further, citizen scientists provide a wealth of additional information through additional annotations via hashtags in discussion boards. 

Our annotated video data set is already being used for AI algorithm training and our findings demonstrate the competence of community scientists with challenging videos, and hold great promise for future studies on animal behaviour and population monitoring. 

And a MASSIVE thank you and panthoot to our amazing mod @Eweforia (Carol) who made this incredible video abstract of our paper

Visit us at ChimpandSee.org today and contribute to research and conservation !

New PanAf paper: Population dynamics and genetic connectivity in recent chimpanzee history

 

Our newest PanAf paper is out now in Cell Genomics, entitled "Population dynamics and genetic connectivity in recent chimpanzee history" 

For a great summary of what we found check out some of our press 

• Scientists produce chimp genetic map to combat trafficking
• U Pompeu Fabra/iDiv/MPI-EVA press release
• Des scientifiques aident à lutter contre le trafic de chimpanzés en étudiant leur ADN
• Scientists Create World's Largest Chimp DNA Genome From Poop

or read lead author Claudia Fontsere's fabulous Twitter thread !

New PanAf chimp microbiomes paper!

The PanAf has a new paper out examing the microbiomes of chimpanzees across their range!

tl;dr: 

Genetics/geography are correlated with prokaryotic and parasite community dissimilarity. When controlling for these, vegetation also has an influence on prokaryotic community composition.

We also found some site-specific differences in prokaryote community composition (though not in Western chimps). 

We discuss how regional tool use for resource extraction might be influencing site-specific differences & compare the patterns observed in chimps to those in humans.

Citation:

Bueno de Mesquita CP, Nichols LM, Gebert MJ, Vanderburgh C, Bocksberger G, Lester JD, Kalan AK, Dieguez P, McCarthy MS, Agbor A, Álvarez Varona P, Ayimisin AE, Bessone M, Chancellor R, Cohen H, Coupland C, Deschner T, Egbe VE, Goedmakers A, Granjon A-C, Grueter CC, Head J, Hernandez-Aguilar RA, Jeffery KJ, Jones S, Kadam P, Kaiser M, Lapuente J, Larson B, Marrocoli S, Morgan D, Mugerwa B, Mulindahabi F, Neil E, Niyigaba P, Pacheco L, Piel AK, Robbins MM, Rundus A, Sanz CM, Sciaky L, Sheil D, Sommer V, Stewart FA, Ton E, van Schijndel J, Vergnes V, Wessling EG, Wittig RM, Ginath YY, Yurkiw K, Zuberbühler K, Gogarten JF, Heintz-Buschart A, Muellner-Riehl AN, Boesch C, Kühl HS, Fierer N, Arandjelovic M*, Dunn RR* (2021) Structure of Chimpanzee Gut Microbiomes across Tropical Africa. Msystems doi: 10.1128/msystems.01269-20

First Chimp&See Paper (and new PanAf paper): Chimpanzee Identification and Social Network Construction through an Online Citizen Science Platform

Our first ChimpandSee.org paper! 

We find that citizen scientists can reliably identify chimpanzees from camera trap videos. 

McCarthy MS, Stephens C, Dieguez P, Samuni L, Després-Einspenner ML, Harder B, Landsmann A, Lynn LK, Maldonado N, Ročkaiová Z, Widness J, Wittig RM, Boesch C, Kühl HS, Arandjelovic M (2020) Chimpanzee Identification and Social Network Construction through an Online Citizen Science Platform. Ecology and Evolution doi : 10.1002/ece3.7128

https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.7128

Video abstract:

Abstract:

Citizen science has grown rapidly in popularity in recent years due to its potential to educate and engage the public while providing a means to address a myriad of scientific questions. However, the rise in popularity of citizen science has also been accompanied by concerns about the quality of data emerging from citizen science research projects. We assessed data quality in the online citizen scientist platform Chimp&See, which hosts camera trap videos of chimpanzees (Pan troglodytes) and other species across Equatorial Africa. In particular, we compared detection and identification of individual chimpanzees by citizen scientists with that of experts with years of experience studying those chimpanzees. We found that citizen scientists typically detected the same number of individual chimpanzees as experts, but assigned far fewer identifications (IDs) to those individuals. Those IDs assigned, however, were nearly always in agreement with the IDs provided by experts. We applied the data sets of citizen scientists and experts by constructing social networks from each. We found that both social networks were relatively robust and shared a similar structure, as well as having positively correlated individual network positions. Our findings demonstrate that, although citizen scientists produced a smaller data set based on fewer confirmed IDs, the data strongly reflect expert classifications and can be used for meaningful assessments of group structure and dynamics. This approach expands opportunities for social research and conservation monitoring in great apes and many other individually identifiable species.

Visit us at ChimpandSee.org and participate in citizen science!

 

New PanAf paper: Chimpanzees show greater behavioural and cultural diversity in more variable environments

An international team of researchers led by Ammie Kalan and Hjalmar Kühl of the Pan African Programme: the Cultured Chimpanzee (PanAf) at the Max Planck Institute for Evolutionary Anthropology compiled a data set combining fieldwork conducted by the PanAf at 46 field sites, plus an in-depth literature search on chimpanzee research. For 144 chimpanzee social groups they investigated the long-standing question of under which environmental conditions chimpanzees acquire more behavioural traits. They used their unique dataset to test whether chimpanzee groups were more likely to possess a larger set of behaviours if they lived in more seasonal habitats or habitats where forest cover repeatedly changed over the last thousands of years. The behaviours largely included tool use and more than half have been described as cultural in previous studies.

Press Release HERE

Original Paper HERE

citation:

Kalan AK, Kulik L, Arandjelovic M, Boesch C, Haas F, Dieguez P, Barratt CD, Abwe EE, Agbor A, Angedakin S, Aubert F, Ayimisin EA, Bailey E, Bessone M, Brazzola G, Buh VE, Chancellor R, Cohen H, Coupland C, Curran B, Danquah E, Deschner T, Dowd D, Eno-Nku M, Fay JM, Goedmakers A, Granjon AC, Head J, Hedwig D, Hermans V, Jeffery KJ, Jones S, Junker J, Kadam P, Kambi M, Kienast I, Kujirakwinja D, Langergraber KE, Lapuente J, Larson B, Lee KC, Leinert V, Llana M, Marrocoli S, Meier AC, Morgan B, Morgan D, Neil E, Nicholl S, Normand E, Ormsby LJ, Pacheco L, Piel A, Preece J, Robbins MM, Rundus A, Sanz C, Sommer V, Stewart F, Tagg N, Tennie C, Vergnes V, Welsh A, Wessling EG, Willie J, Wittig RM, Yuh YG, Zuberbuehler K, Kühl HS (2020) Environmental variability supports chimpanzee behavioural diversity. Nature Communications 11 (4451) doi: 0.1038/s41467-020-18176-3

New PanAf paper: Chimpanzee Ethnography Reveals Unexpected Cultural Diversity

How complex are chimpanzee cultures?
Chimpanzee groups each have their own unique termite fishing cultures

The transmission of cultures from generation-to-generation is only found in a few species besides humans. Chimpanzees are one such species and exhibit a large diversity of cultural and tool use behaviours. Although these behaviours have been well documented at a handful of long term research sites, the true cultural repertoire of chimpanzees across populations is still poorly understood. To better understand this diversity, researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, initiated the ‘Pan African Programme: The Cultured Chimpanzee’ (PanAf) in 2010. Using a standardized protocol, researchers set up camera traps, collected samples and recorded ecological data at over 40 temporary and long-term research sites across Africa.

Prior to this study, termite fishing was thought to occur in only two forms with one or multiple tools, from either above-ground or underground termite nests. By carefully observing the techniques required to termite fish at 10 different sites, lead author Christophe Boesch created a catalogue of behaviours (or ethogram) for each chimpanzee in the study.

What was found was 38 different technical elements making up the various termite fishing techniques, all of which were combined in different ways in each of the chimpanzee communities. In addition, individuals in the same community shared more of the termite fishing technical elements, and unique combinations of the technical elements, when compared to chimpanzees from other groups. 

“The diversity of techniques seen in chimpanzee termite fishing was a huge surprise to me. Not only does each community have a very unique way of fishing, they also combine a number of different elements into specific termite fishing etiquettes” explains Dr. Christophe Boesch “the most striking examples of this are how the Wonga Wongue chimpanzees of Gabon usually lie down on their sides to termite fish, while the Korup chimpanzees in Cameroon lean on their elbows, and the ones from Goualougo in the Republic of Congo sit while fishing”.

Wonga Wongue, Gabon

Korup, Cameroon

Goualougo, R-Congo

Because the communities of chimpanzees live in similar habitats with access to the same resources, ecological differences could mostly be ruled out to explain the observed differences. “This supports the idea that chimpanzees are capable of imitating social techniques in ‘how to termite fish’ which goes beyond alternative explanations such as each individual reinventing termite fishing each time they learn it” explained co-author Ammie Kalan.

Much like in human etiquette, not everything is about increased efficiency but rather about conforming to what the rest of the group is doing. In humans, this is observed in the different chopstick cultures across Asia. “For example, in Thailand and Japan not only are chopsticks somehow shaped differently, but the way they hold them differ as well, and this is very reminiscent of what we see here with chimpanzees. In La Belgique in Cameroon, chimpanzees fashion their stick by opening the fibers to obtain a long brush and then rest the termite-covered stick on their wrist while they eat. On the other hand, at another site in Cameroon called Korup, the chimpanzees do not make a brush at all and use their mouth to shake the inserted stick while it is in the mound”, explains Christophe Boesch.

La Belgique, Cameroon

In humans, cultural variation has been documented in hundreds of different populations which is one explanation for why chimpanzee culture seems so limited in comparison. “What we knew before about chimpanzees came from at most 15 communities” noted co-author Hjalmar Kuehl,  “through the PanAf we have been able to study many more communities and by this we are able to learn more about the richness of chimpanzee diversity and culture and could demonstrate that there is so much more to discover out there.”

Further analyses of videos and other data collected from the PanAf are currently underway. “Termite fishing and other cultural behaviours of wild chimpanzees can be observed first hand by signing onto our citizen science platform Chimp&See”, says co-author Mimi Arandjelovic. At Chimp&See citizen scientists can watch the over 1 million video clips the PanAf has recorded from all across Africa of chimpanzees, gorillas, elephants, buffalo, leopards and many more species. Visit www.chimpandsee.org and you could be a citizen scientist contributing to analyzing data and help with further discoveries in the wild!

citation:
Boesch C, Kalan AK, Mundry R, Arandjelovic M, Pika S, Dieguez P, Ayimisin EA, Barciela A, Coupland C, Egbe VE, Eno-Nku M, Fay JM, Fine D, Hernandez-Aguilar RA, Hermans V, Kadam P, Kambi M, Llana M, Maretti G, Morgan D, Murai M, Neil E, Nicholl S, Ormsby LJ, Orume R, Pacheco L, Piel A, Sanz C, Sciaky L, Stewart FA, Tagg N, Wessling EG, Willie J, Kühl HS (2020) Chimpanzee Ethnography Reveals Unexpected Cultural Diversity. Nature Human Behaviour doi: 10.1038/s41562-020-0890-1
https://www.nature.com/articles/s41562-020-0890-1

• Press release in English
• Pressemitteilung auf Deutsch

Inclusive chimpanzee conservation

"Thanks to a pair of great primatologists we had the chance to highlight chimpanzee conservation in a recent letter published today in Science. Check out the important discussion about culture, conservation and of course chimps!" - Ammie Kalan

Read the letter and the PanAf response here: https://science.sciencemag.org/content/sci/364/6445/1040.2.full.pdf

Novelty Response of Wild African Apes to Camera Traps

Another new paper from Ammie Kalan and collaborators including data from the PanAf and Chimp& See's animal selfie's miniproject!! :) Thanks to all the citizen scientists who helped hashtag camera reaction videos !!!

Novelty Response of Wild African Apes to Camera Traps (Current Biology)

And watch some best of videos HERE

Highlights
• Bonobos and gorillas had stronger looking impulses compared to chimpanzees
• Young apes looked longest at camera traps compared to mature individuals
• Presence of a research site or conspecifics reduced the duration of looking
• Both social and environmental factors affect great ape curiosity in the wild

Abstract
Temperament and personality research in humans and nonhuman animals measures behavioral variation in individual, population, or species-specific traits with implications for survival and fitness, such as social status, foraging, and mating success. Curiosity and risk-taking tendencies have been studied extensively across taxa by measuring boldness and exploration responses to experimental novelty exposure. Here, we conduct a natural field experiment using wildlife monitoring technology to test variation in the reaction of wild great apes (43 groups of naive chimpanzees, bonobos, and western gorillas across 14 field sites in Africa) to a novel object, the camera trap. Bonobo and gorilla groups demonstrated a stronger looking impulse toward the camera trap device compared to chimpanzees, suggesting higher visual attention and curiosity. Bonobos were also more likely to show alarm and other fearful behaviors, although such neophobic (and conversely, neophilic) responses were generally rare. Among all three species, individuals looked at cameras longer when they were young, were associating with fewer individuals, and did not live near a long-term research site. Overall, these findings partially validate results from great ape novelty paradigms in captivity. We further suggest that species-typical leadership styles and social and environmental effects, including familiarity with humans, best explain novelty responses of wild great apes. In sum, this study illustrates the feasibility of large-scale field experiments and the importance of both intrinsic and extrinsic factors in shaping animal curiosity.

Press release:
Wild African ape reactions to novel camera traps

Human impact erodes chimpanzee behavioral diversity

photo: Liran Samuni

We are so super proud to announce the publication of our latest PanAf paper "Human impact erodes chimpanzee behavioral diversity" We hope it helps spur the call-to-action for conserving chimps and their behaviours across their range! 

Abstract:
Chimpanzees possess a large number of behavioral and cultural traits among non-human species. The ‘disturbance hypothesis’ predicts that human impact depletes resources and disrupts social learning processes necessary for behavioral and cultural transmission. We used an unprecedented data set of 144 chimpanzee communities, with information on 31 behaviors, to show that chimpanzees inhabiting areas with high human impact have a mean probability of occurrence reduced by 88%, across all behaviors, compared to low impact areas. This behavioral diversity loss was evident irrespective of the grouping or categorization of behaviors. Therefore, human impact may not only be associated with the loss of populations and genetic diversity, but also affects how animals behave. Our results support the view that ‘culturally significant units’ should be integrated into wildlife conservation.

Paper: 
Kühl HS, Boesch C, Kulik L, Haas F, Arandjelovic M, Dieguez P, Bocksberger G, McElreath MB, Agbor A, Angedakin S, Ayimisin EA, Bailey E, Barubiyo D, Bessone M, Brazzola G, Chancellor R, Cohen H, Coupland C, Danquah E, Deschner T, Diotoh O, Dowd D, Dunn A, Egbe VE, Eshuis H, Fernandez Rumen, Ginath Y, Goedmakers A, Granjon AC, Head J, Hedwig D, Hermans V, Imong I, Jeffery KJ, Jones S, Junker J, Kadam P, Kambere M, Kambi M, Kienast I, Kujirakwinja D, Langergraber K, Lapuente J, Larson B, Lee K, Leinert V, Llana M, Maretti G, Marrocoli S, Mbi TJ, Meier AC, Morgan B, Morgan D, Mulindahabi F, Murai M, Neil E, Niyigaba P, Ormsby LJ, Pacheco L, Piel A, Preece J, Regnaut S, Rundus A, Sanz C, van Schijndel J, Sommer V, Stewart F, Tagg N, Vendras E, Vergnes V, Welsh A, Wessling EG, Willie J, Wittig RM, Yurkiw K, Zuberbuehler K, Kalan AK (2019) Human impact erodes chimpanzee behavioral diversity. Science. doi: 10.1126/science.aau4532


Press: 

• We Are Destroying Chimpanzee Cultures (Ed Yong, The Atlantic)
• Humans are wiping out chimpanzee cultures (Gretchen Vogel, Science magazine)
• Human encroachment threatens chimpanzee culture (Sujata Gupta, Science News)
• Dr. Ammie Kalan on the BBC live!
• Chimps varied ‘culture’ matters for conservation, study says (Christina Larson, Associated Press)
• MPI Press Release English
• MPI Press Release Deutsch
• ...and more

Video Abstract:

New paper: An assessment of the efficacy of camera traps for studying demographic composition and variation in chimpanzees (Pan troglodytes)

New seminal paper from the PanAf's Maureen McCarthy and colleagues at the Tai Chimpanzee Project

An assessment of the efficacy of camera traps for studying demographic composition and variation in chimpanzees (Pan troglodytes)

https://onlinelibrary.wiley.com/doi/full/10.1002/ajp.22904

Abstract
Demographic factors can strongly influence patterns of behavioral variation in animal societies. Traditionally, these factors are measured using longitudinal observation of habituated social groups, particularly in social animals like primates. Alternatively, noninvasive biomonitoring methods such as camera trapping can allow researchers to assess species occupancy, estimate population abundance, and study rare behaviors. However, measures of fine‐scale demographic variation, such as those related to age and sex structure or subgrouping patterns, pose a greater challenge. Here, we compare demographic data collected from a community of habituated chimpanzees (Pan troglodytes verus) in the Taï Forest using two methods: camera trap videos and observational data from long‐term records. By matching data on party size, seasonal variation in party size, measures of demographic composition, and changes over the study period from both sources, we compared the accuracy of camera trap records and long‐term data to assess whether camera trap data could be used to assess such variables in populations of unhabituated chimpanzees. When compared to observational data, camera trap data tended to underestimate measures of party size, but revealed similar patterns of seasonal variation as well as similar community demographic composition (age/sex proportions) and dynamics (particularly emigration and deaths) during the study period. Our findings highlight the potential and limitations of camera trap surveys for estimating fine‐scale demographic composition and variation in primates. Continuing development of field and statistical methods will further improve the usability of camera traps for demographic studies.

New publication using Chimp&See data investigates nocturnal activity in wild chimpanzees

The Pan African Programme: The Cultured Chimpanzee (PanAf) in collaboration with Dr. Nikki Tagg Nama (PGS Cameroon, Royal Zoological Society of Antwerp) have just published a research paper investigating the nocturnal activities of wild chimpanzees. Using data from camera trap videos annotated on Chimp&See and from the PanAf collection, the researchers have been interested in the influence of different environmental factors that could lead to more nighttime activities of chimpanzees and possibly disturb their sleeping patterns.

Chimpanzees are rarely active at night after building their nests. So, it was a surprise for me and other volunteers at Chimp&See to see them on our camera trap videos at almost all sites at least occasionally walking in the darkness. We decided to tag and collect those videos. While only a tiny fraction of videos at Chimp&See show what we call the “nightchimps”, it is an interesting phenomenon and leads to questions about what general or site-specific environmental circumstances might cause more or less nocturnal activities.
After starting and curating the Chimp&See “nightchimps” collection, we got the chance to join the project to get a different perspective on the science part and support the science team beyond our regular Chimp&See moderators’ tasks.

Using the nighttime video clips identified and tagged by our volunteers and video material from other PanAf research sites, as well as associated data from environmental surveys of these sites, this study provides a first comprehensive analysis of nocturnal chimpanzee activity in the wild spanning their range and all four subspecies. The study shows that chimpanzees indeed are active at night on the terrestrial camera trap videos at almost all sites (18 out of 22 in the study), but only infrequently, making it a rare behavior still. From all observed chimpanzee activity in the videos only 1.8% occurred at night, but this amount differed from site to site considerably, from 0 videos to more than 8% of all observed chimpanzee activity at one site. The video material shows chimpanzees mostly traveling during these times, but also some social activities and feeding.

The researchers then tested whether different environmental factors like percentage of mature forest at a given site, the abundance of predators (lions, leopards, and hyenas), the abundance of other large mammals (buffalos and elephants), average daily temperature, rainfall, observed human activity, and the percentage of moon illumination on a given night affect the probability of observing chimpanzee nocturnal activity. Only three of these factors showed an effect on increased night activity: lower levels of human activity, more forest coverage of the site, and higher day temperatures – as we’ve seen at the Chimp&See site “Dry Lake” during the dry season.

As data was collected exclusively via camera trap videos, the authors speculate that these initial data might underestimate the amount of nocturnal activity. When more camera trap videos become available in the future – including at Chimp&See – they hope to find more evidence for nocturnal behaviors and its relevance for conservation and also human evolution.

This study demonstrates the unique advantage of using camera traps to find and investigate new and rare behaviors in chimpanzees and other animals, here especially those occurring at night. While it is possible to watch chimpanzees by staying at the nesting site all night, this can only be done at one of the few sites with habituated chimpanzees and a dedicated nocturnal field team. Moreover, the huge collaborative effort of the PanAf program provides the first opportunity to compare sites, environmental factors, and different populations to learn more about the evolutionary drivers of chimpanzee behavior.

• Watch the Chimp&See “nightchimps” collection here.
• More information about the Pan African Programme: The Cultured Chimpanzee and its mission.
• Original publication: Tagg, N. et al.  “Nocturnal activity in wild chimpanzees (Pan troglodytes): Evidence for flexible sleeping patterns and insights into human evolution” American Journal of Physical Anthropology, 166(3), 510-529.

If you want to join Chimp&See helping us to find more exciting chimpanzee videos and, for instance, contribute to the leopard mini-project please visit www.chimpandsee.org!

A new chimpanzee behavioural variant! Algae fishing in Bakoun, Guinea

We began the Pan African Programme: the Cultured Chimpanzee (PanAf) in the hopes of discovering new chimpanzee cultures and cultural variants in previously poorly- and unstudied populations. Earlier this year we documented the occurrence of a new behaviour, chimpanzee accumulative stone throwing, present in four populations in West Africa. Today we are happy to announce the publication of our new study reporting on an new behavioural variant of algae fishing by chimpanzees in Guinea!

We describe the first camera trap footage of algae fishing behaviour at a PanAf temporary research site in Bakoun, Guinea where the tool-use appears quite different from what is known from a nearby long-term chimpanzee site at Bossou, Guinea and also differs from previous reports of rare algae scooping in Congo. 

All age and sex classes of Bakoun chimpanzees were observed to successfully fish for algae in a river, stream or pond using woody branches or twigs as fishing rods. The tools were on average longer and sturdier than the algae fishing tools described at Bossou. 

The freshwater green algae being targeted was of the same genus, Spirogyra, that is fished at Bossou, but grows on the bottom of the river and stream beds and does not collect on the surface as it does at Bossou. As such, the ecology of the particular algae growing at each site may drive the types of tools necessary to harvest the algae. We suggest that the algae likely provides a substantial nutritional benefit to the chimpanzees at Bakoun, especially during the dry season when chimpanzees were observed to fish for up to an hour at the same spot. 

These videos have not yet been up on Chimp&See yet and you can see that one of the limitations of our study was that the chimps from these videos have not yet been identified. We're hoping to have these up sometime in 2017 and look forward to matching some chimps with you then!

Citation:
Boesch C, Kalan AK, Agbor A, Arandjelovic M, Dieguez P, Lapeyre V, Kühl HS (2016) Chimpanzees routinely fish for algae with tools during the dry season in Bakoun, Guinea. American Journal of Primatology doi 10.1002/ajp.22613

That time when Elon Musk tweeted about our research !!!

#ChimpanzeeAccumulativeStoneThrowing

Stone throwing Gif :)

COOL! we got some new stone throwing gifs from this article: 
https://www.thedodo.com/mysterious-chimpanzee-behavior-gives-researcher-goose-bumps-1636949303.html

The great one of Dodge above can be found at:
https://assets-animated.rbl.ms/4316151/980x.gif

Chimpanzee Accumulative Stone Throwing - our 1st PanAf paper!

Our very first PanAfrican Programme: the cultured chimpanzee paper is out today in Scientific Reports!

We have already had some stone throwing videos up on Chimp&See, you can check them out at the #stonethrow tag group! Below is one of our favourites of Dodge demonstrating hurling a rock at an accumulative stone throwing site:

original video can be found at 

http://talk.chimpandsee.org/#/subjects/ACP0005652

You can check out the press release here! (German version here) 

and the original paper here!

Chimpanzee accumulative stone throwing

Abstract of the paper:

The study of the archaeological remains of fossil hominins must rely on reconstructions to elucidate the behaviour that may have resulted in particular stone tools and their accumulation. Comparatively, stone tool use among living primates has illuminated behaviours that are also amenable to archaeological examination, permitting direct observations of the behaviour leading to artefacts and their assemblages to be incorporated. Here, we describe newly discovered stone tool-use behaviour and stone accumulation sites in wild chimpanzees reminiscent of human cairns. In addition to data from 17 mid- to long-term chimpanzee research sites, we sampled a further 34 Pan troglodytes communities. We found four populations in West Africa where chimpanzees habitually bang and throw rocks against trees, or toss them into tree cavities, resulting in conspicuous stone accumulations at these sites. This represents the first record of repeated observations of individual chimpanzees exhibiting stone tool use for a purpose other than extractive foraging at what appear to be targeted trees. The ritualized behavioural display and collection of artefacts at particular locations observed in chimpanzee accumulative stone throwing may have implications for the inferences that can be drawn from archaeological stone assemblages and the origins of ritual sites.

The PanAf is made up of a network of amazing collaborators who made this paper possible, please check them out at: http://panafrican.eva.mpg.de/english/team.php