While throwing, the chimpanzees pant hoot \u2014 a loud, long-distance communicative signal<\/a> \u2014 and sometimes repeatedly hit their hands and feet<\/a> on the tree in a behaviour called buttress drumming<\/a>. <\/p>\n We have just returned from a field site in Guinea-Bissau where we collected data to help us investigate the social and ecological context of accumulative stone throwing to determine what these chimpanzees are trying to communicate.<\/p>\n Given our evolutionary relatedness to chimpanzees<\/a>, we hope accumulative stone throwing can help us understand the emergence of complex communication and stone tool use<\/a> over the course of human evolution.<\/p>\n A cultural behaviour<\/p>\n Pant hooting and buttress drumming are both part of the male chimpanzee display, suggesting that accumulative stone throwing might represent a modification of this common behaviour. It is likely a cultural behaviour<\/a> due to its limited distribution, and because the availability of rocks and trees does not guarantee the presence of an accumulative stone throwing site. <\/p>\n Dr. Jane Goodall pant hoots with chimpanzees.<\/p>\n Previous research suggests that accumulative stone throwing is likely communicative<\/a> or may even have a symbolic purpose, with sites marking important locations within the chimpanzees\u2019 territory. <\/p>\n However, we still don\u2019t know what accumulative stone throwing sites might mean to the chimpanzees themselves nor why they do it. While some primates use stone tools to access food, for instance to crack open nuts<\/a>, accumulative stone throwing is a rare example of stone tool use in a social context. It has been observed in only four chimpanzee groups in West Africa to date.<\/p>\n Setting up camp<\/p>\n We travelled to the remote Bo\u00e9 chimpanzee territory in Guinea-Bissau and based ourselves in B\u00e9li, a small village where, in collaboration with local people, the Dutch non-governmental organization Chimbo<\/a> maintains a compound. Visiting researchers and tourists can stay here and use a workspace with solar-generated electricity. <\/p>\n From B\u00e9li, we cycled and hiked 22 kilometres into the savanna-woodland to establish a bush camp with our two field assistants, Djei Bald\u00e9 and Balu S\u00e9ra, and a master\u2019s student from the Great Ape Behaviour Lab<\/a>, Taylor Tippett. <\/p>\n The Bo\u00e9 chimpanzees performing the behaviour are unhabituated; they are not used to humans, meaning that we cannot observe individual chimpanzees on foot because they will run away. Instead, we collected behavioural data using camera traps and recording devices. <\/p>\n Author Ammie Kalan and field assistant Balu S\u00e9ra set up a camera trap near an accumulative stone throwing site. We set up two video cameras at each accumulative stone throwing site and placed the recording devices strategically to capture audio data from the areas around these sites.<\/p>\n Our campsite bordered the Fefine, a large river that flows even in the dry season. In a landscape like the savanna-woodland where water sources are scarce, rivers like the Fefine are important for wildlife and humans alike. We captured several of our neighbours on cameras set up near the riverbank.<\/p>\n A hippopotamus captured on camera by the river near our camp. Chimpanzee nests<\/p>\n On an average day, we woke up around 6:30 a.m. and ate a small breakfast before heading to a set of two to five sites. There, we replaced the SD cards and batteries on the cameras, made sure the devices were working well and collected any additional data needed, including measurements of the tree and 3D scans of rocks thrown at the tree for later analysis. <\/p>\n Along the way, we recorded observations of chimpanzee nests, feeding signs, vocalizations and sightings. <\/p>\n The video and audio data we collected will allow us to investigate the social traits of accumulative stone throwing, including the age and sex of the stone thrower and the audience (other chimpanzees nearby who might react to the throw). This information can help us determine what chimpanzees are trying to communicate.<\/p>\n We found that most of the sites first identified by the Pan African Programme<\/a>, and revisited by our team in 2017, were still in use during our recent trip to the field, meaning that chimpanzees can use these sites for over a decade.<\/p>\n Our campsite featuring a canopy built by our guides. The threat of bauxite mining<\/p>\n As many primate species face threats from human activities, cultural behaviours and the maintenance of rich cultural repertoires can help them adapt to environmental changes<\/a> and provide support for conservation<\/a>. <\/p>\n On top of its potential communicative importance and intrinsic value as a cultural behaviour, accumulative stone throwing involves durable primate material culture, the loss of which would constitute the erasure of primate heritage<\/a>. <\/p>\n Unfortunately, chimpanzee habitat in Guinea-Bissau is threatened by extractive industries, particularly industrial mining<\/a>. While in the field, we encountered bore holes from bauxite mining exploration. <\/p>\n Bauxite mining represents a significant opportunity for economic growth and development<\/a> in Guinea-Bissau. It can also cause habitat destruction and pollution with severe detrimental effects for chimpanzees, other wildlife and the local people \u2014 as it already has in neighbouring Guinea. <\/p>\n Environmental oversight and regulations are much needed, especially given the added challenges of unstable governance in Guinea-Bissau<\/a>.<\/p>\n A bauxite mining site in 2017 near the village of Sangaredi in Guinea. By studying and bringing attention to chimpanzee cultural behaviours like accumulative stone throwing, we hope to support chimpanzee conservation<\/a> and the maintenance of biodiversity more broadly<\/a>, as well as the preservation of primate cultural materials for future research and education.<\/p>\n","protected":false},"excerpt":{"rendered":"Walking through the savanna-woodland landscape of Bo\u00e9 National Park, Guinea-Bissau, you might encounter a tree covered in gnarled…\n","protected":false},"author":2,"featured_media":472904,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[85,46,141,386],"class_list":["post-472903","post","type-post","status-publish","format-standard","has-post-thumbnail","category-wildlife","tag-il","tag-israel","tag-science","tag-wildlife"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/472903","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=472903"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/472903\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/472904"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=472903"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=472903"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=472903"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Two](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2026\/06\/file-20260507-57-xs381v.JPG\")
<\/p>\n
\n (Taylor Tippett)<\/p>\n![\"Hippopotamus](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2026\/06\/file-20260507-57-5hehvt.JPG\")
<\/p>\n
\n (Robyn Nakano)<\/p>\n![\"Three](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2026\/06\/file-20260507-57-b0kb3w.jpg\")
<\/p>\n
\n (Taylor Tippett)<\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2026\/06\/file-20260511-57-cwr6h7.JPG\")
<\/p>\n
\n (Ammie Kalan)<\/p>\n