Wild chimpanzees have been observed smashing, bashing, and stashing wild tortoises for food in a world first. Writing in Scientific Reports, researchers working in Gabon’s Loango National Park say their findings shed light on the behavior and dietary practices that may inform how early humans evolved.
A total of 38 prey events by 10 different chimps were seen between 2016 and last year. In each instance, an adult male chimp discovered and captured its tortoise prey, then smashed it repeatedly against a wooden anvil – sometimes traveling up to 50 meters (165 feet) before doing so – before climbing into a tree to savor its meal.
"We have known for decades that chimpanzees feed on meat from a variety of animal species, but until now the consumption of reptiles has not been observed", said primatologist Tobias Deschner, from the Max Planck Institute for Evolutionary Anthropology, in a statement. "What is particularly interesting is that they use a percussive technique that they normally employ to open hard-shelled fruits to gain access to meat of an animal that is almost inaccessible for any other predator."
It wasn’t just the adult males, either. Juvenile chimps were seen unsuccessfully trying to follow in their elders’ footsteps but either lacked the skill or strength to successfully crack open the tortoise’s shell. In fact, most mastered their tortoise-smashing ability between 9 and 10 years old. In the end, even those unsuccessful “turtle smashers” were given meat in peaceful and cooperative sharing events.
"Sometimes, younger animals or females were unable to crack open the tortoise on their own. They then regularly handed the tortoise over to a stronger male who cracked the tortoise's shell open and shared the meat with all other individuals present," said study author Simone Pika.
One event particularly stuck out in the minds of researchers. An adult male was seen cracking a shell and eating half of the tortoise while he sat in a tree. He then tucked the rest of his reptilian meal into a tree, climbed down, and slept for the night. The next morning, he returned to his leftovers for breakfast.
"This indicates that chimpanzees may plan for the future," said Pika. "The ability to plan for a future need, such as for instance hunger, has so far only been shown in non-human animals in experimental and/or captive settings. Many scholars still believe that future-oriented cognition is a uniquely human ability. Our findings thus suggest that even after decades of research, we have not yet grasped the full complexity of chimpanzees' intelligence and flexibility.”
A number of animals, from birds to bottlenose dolphins, employ tools to make their lives easier, but understanding how one of our closest living relatives uses various mechanisms to survive shows us how our early ancestors may have evolved. An unrelated study published this week found that chimpanzee groups also employ policemen for impartial intervention in order to resolve conflict. This morally motivated behavior guarantees the stability of their group to benefit the community as a whole.