As part of a special issue in Behaviour on anecdotes, we describe how an immigrant chimpanzee female adopted a local female-specific tradition after introduction to a captive group. A thread 1/8
With my wonderful co-authors @ejcvanleeuwen, @cwebb218, and Frans de Waal, we provide the first report of this tradition, we dubbed the "crossed-arm walk" (see gif), which has been present in the chimpanzee group @burgerszoo for over 20 years. 2/8
When two new females (Moni, left, and Erika, right) were introduced to the group, Moni copied the crossed-arm walk days after meeting only the resident female in the gif above. Erika never showed the behavior during >1 year of observation. 3/8 📷:@KaylaKolff
Two years later, Moni, who copied the behavior, appeared more socially integrated than Erika. This could of course be due to other things as well (notably see our other publication on Moni experiencing a stillbirth) 4/8 link.springer.com/article/10.100…
Still, our findings may also point towards a known phenomenon in humans: similarity breeding connection. Adopting the crossed arm walk may have helped Moni integrate in her new group. Moni was also in a more socially insecure position than Erika at the start of introduction. 5/8
Previous studies have shown chimpanzees adopting local conventions after migration, but in our report the speed at which Moni copied the behavior (within days after being exposed to it) is especially remarkable. 6/8
This anecdote illustrates that immigrant female chimpanzees can show different behaviors during the integration process. Introducing chimpanzees to a new group isn't easy, and new individuals may use strategies like behavioral copying to mitigate the risk of exclusion. 7/8
Lastly, we wouldn't be able to write this article without the zookeepers and their amazing records, so a big thank you to them!
And to the chimpanzees themselves of course! Especially Moni for single-handedly inspiring two publications 🐵
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And truly last, a very big thank you to @KaylaKolff for helping with the data collection! She was my partner in crime during the first (biggest) chunk of observations, and you should definitely check out her research on jealousy in these chimps! link.springer.com/article/10.100…
Over 4 years after the start of data collection, our study showing qualitative variation in abnormal behavior in chimpanzees has finally been published in Animal Welfare (@UFAW_1926).
A short thread on what we found and why this matters 1/10
With my co-authors Elisabeth Sterck, Frans de Waal, and @cwebb218, we explore how a group of captive chimpanzees varies in their expression of abnormal behavior (AB). AB, such as coprophagy (eating one’s feces, see GIF) is often seen as a sign of poor welfare. 2/10
But by definition, AB is not necessarily negative, it is simply behavior observed in captive animals that is less common or entirely absent in wild populations. Wild chimpanzees also eat their feces to re-ingest seeds, but nowhere near as frequently as zoo chimpanzees.
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