Using Special Tasks to Gauge How Chimpanzees Think

“Ooh, ooh, ooh ooh!” Ellie, a petite chimpanzee with an intense demeanor, food grunts loudly to show her excitement over seeing fruit cereal being dropped several feet in front of her enclosure. She anxiously grabs the tool provided by the keeper that allows her to reach the colorful cereal. Then she quickly begins shoveling the tasty treats toward her, eating them with delight.

Chimpanzee Ellie uses a tool to gather fruit cereal at the Center for Great Apes sanctuary in Wauchula, Florida. It's one of the tasks being studied to better understand how chimpanzees raised with humans think differently than those reared in natural social groups.

In my last blog entry as part of my research for Project ChimpCARE, I discussed collecting behavioral observations to help understand how having been a pet or in entertainment impacts chimpanzees living in the United States. Beyond understanding differences in everyday behaviors, we also want to gauge specialized behaviors that require a task to explore, such as cognition, reaction to novelty and social tolerance.

The task Ellie is doing above helps us understand how she thinks and uses human-designed objects. The tool she uses to get the treats is more efficient on one side than the other. Ellie easily figures out she can get the cereal faster if she uses the shovel compared to the pointy side. However, this isn’t the case for all chimpanzees that try to use the tool.

Ellie, who is now living at the Center for Great Apes sanctuary in Wauchula, Florida, was pulled from her mother at birth and grew up in the entertainment industry “working” with people and different types of tools designed by people. Chimpanzees who were raised by their mothers in zoos may not have this exposure to using different tools, so they might either take longer to get the cereal with the pointy end or might never get the cereal at all. This task shows how chimpanzees raised completely or nearly completely by humans might learn different skills compared to those raised by their mothers.

The other two tasks I’m observing are a novel object task and a peanut food-sharing task. The novel object task involves attaching a blue flying-saucer sled—something none of these chimps have seen previously—to the outside of their enclosure for 30 minutes. During this time I watch to see if the chimpanzees want to interact with the object or if they run away from it.

If they do interact with the sled, I want to see if they try to destroy it or just touch and lick it. Chimpanzees living as pets or in entertainment have probably had more exposure to a wide variety of objects compared to chimpanzees living in zoos, so they might not be as interested in the object.

The peanut food-sharing task was actually developed by Katherine Cronin, a former Lincoln Park Zoo researcher who is currently working at Chimfunshi, a sanctuary in Africa. The task was developed to look at how chimpanzees interact with each other when given a limited quantity of peanuts in a 3-foot area. I’m looking to see if chimpanzees who were raised with people have a different reaction to having to share food compared with chimpanzees who have always lived with other chimpanzees.

Chimpanzees raised as pets or in entertainment often have no or limited experience with other chimpanzees, so they might not be as good at reading that another chimpanzee is mad over not getting enough peanuts. This could result in more disputes for chimpanzees without proper chimpanzee social skills.

Hopefully these tasks will give us a better understanding of how chimpanzees who were raised solely or primarily by humans think and behave differently from those raised by other chimpanzees, thereby allowing us to better care for them now and in the future.

Hani Freeman

Hani Freeman, Ph.D., is a postdoctoral fellow in Lincoln Park Zoo's Lester E. Fisher Center for the Study and Conservation of Apes.


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