Field experiments, ecology and physiology: studying cultural propensities in wild species

This blog post is provided by Kelly Ray Mannion and tells the #StoryBehindthePaper for the paper ‘A multicomponent approach to study cultural propensities during foraging in the wild‘, which was recently published in Journal of Animal Ecology. In their paper, they review previous work done with field experiments, how to assess diet and ecology, as well as physiology to offer a framework to study cultural propensities in wild species.

Uganda is quite the hotspot for primate research. Home to Bulindi, Kibale and Budongo chimpanzees as well as Bwindi mountain gorillas. And with each passing month, thanks to the Bugoma Primate Conservation Project which has been working to habituate some of the several chimpanzee communities in Bugoma Forest Reserve in western Uganda, researchers learn more and more about the chimps living in the forest there.

Semi-habituated: that means there are days where we spend hours with chimps and days where it seems like they’ve hitched a ride with a passing boda boda and haven’t left a note about when they’ll be back. It’s an exciting time to be working in Bugoma because we get to learn about these “new-to-us” communities and see how they fit in with the rest of the Ugandan chimps. And the big question on people’s mind is, do they use tools?!

Hey Google, what are the drivers of tool-use?”. As a PhD student with this as my thesis topic, it was worth a shot. The literature surrounding culture and cultural behaviors like tool-use is immense and yet still growing. Although not without its criticisms, learning that culture exists in non-human species has not lost its shock value or appeal to researchers. Moreover, disentangling the factors which influence cultural propensities is still full of debate with many projects and hypotheses aimed at understanding what the root causes of these behaviors are. So, doing a PhD investigating drivers of tool-use behaviors leads us down a rabbit hole.

Semi-habituated, i.e., we’ve still got a lot to learn about these chimps. The presence or absence of tool-use seems like a great place to start. Of course, directly observing these behaviors in fully habituated chimpanzees would be ideal, but field experiments in communities that are not fully habituated, such as the Bugoma chimpanzees can really help bring this information to light. And for my PhD specifically, I am conducting the honey-trap experiment which has been done previously in other Ugandan chimpanzee communities.

Figure 1: PhD student Kelly Ray Mannion sets up the honey-trap experiment with the help of Bugoma Primate Conservation Project field assistants. (photo: Nisheet Patel)

The honey-trap experiment uses a log with a hole in it to simulate a natural beehive which chimpanzees can encounter in the forest. The honey is in the bottom of the hole and only accessible through a small opening, thus creating a situation where the chimps cannot reach it with their fingers and must figure out how to extract the honey. Chimpanzee behavior is recorded via motion sensing camera traps. So, the honey-trap experiment can help answer the question of tool-use behaviors among others like social learning, curiosity, information diffusion, etc. Next, is to understand what influences these behaviors (or lack thereof).

Figure 2: Screenshot from a camera trap video of Bugoma Forest chimpanzees interacting with the honey-trap experiment. (photo: Kelly Ray Mannion)

The field is not lacking in ideas for what to study, how to study it, nor hypotheses to consider. For example, it’s hard to analyze tool-use behavior and not address the necessity or opportunity hypotheses: is necessity the mother of all invention, or are ingenuous behaviors arising from opportune moments? Here’s how I will explain these hypotheses and the overall goal of my project to my grandmother: Imagine coming home from work hungry-bordering-on-hangry. What do you do? A) cook a pasta dinner on the stove (takes some time and knowledge to do so) or B) eat the open crackers in the pantry, followed by cupcake on the counter, and topped off with the random carrot in the fridge (most readily available and you only need to know how to chew)? Well, I guess it depends… but depends on what? And that’s what I want to find out. The list of potential factors could go on and on. Maybe it matters what I have eaten earlier that day or if I went to the gym. Perhaps there’s a social component like do I have guests coming over or are my roommates around to witness me scavenge the kitchen area? Because my exhibited behavior is centered around food let’s consider diet, items that are eaten and those that are available, as a general category which can impact my decision. Then, let’s consider how I am feeling, which is related to my diet because it corresponds to what my body needs in terms of energy and nutrients. Even though there are other potential factors, diet and physiology are prominent and so I will start with these.

Following this logic, I incorporate the same factors with the chimps in Bugoma. Diet information comes from observations and inspecting fresh dung samples. Collecting urine samples provides vital information about the stress, energetics, and overall health of the individuals. Combining all this information together gives a fuller picture into the influences of behavior and specifically to know more about the physiological underlying of behavior, which is a core goal of the ECCEpan group, headed by Dr. Thibaud Gruber.

This all seems very primate-centric, human or not, but the same premise can be applied for many other species – field experiment, ecology (diet) and physiology – to understand potential cultural behaviors. It won’t be without some creativeness, imagination and tenacity for the case of some species, but combining as many potential factors as possible gives us a sharper image on what influences cultural propensities in the wild.

About the Author

I am a PhD student at the University of Geneva, part of the ECCEpan group led by Prof. Thibaud Gruber. As a part of my PhD project, I am investigating drivers of tool-use behavior in wild chimpanzees and trying to understand influences of tool-use behavior from an ecological and physiological perspective. I have experience working with chimpanzees, gorillas, orangutans and bonobos and love all things primate and nature related.

Read the paper

Read the full paper here: Mannion, K.R., Ballare, E.F., Marks, M. & Gruber, T. (2022). A multicomponent approach to studying cultural propensities during foraging in the wild.  Journal of Animal Ecology https://doi.org/10.1111/1365-2656.13820

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