History has shown that raising a chimp among humans can end badly. Now, a new study sheds light on why such an upbringing can be costly for chimps as well. Scientists concluded that chimpanzees raised as pets or performers from an early age suffer long-term behavioral problems as a result.
Researchers studied the behaviors of 60 chimpanzees living in either zoos or sanctuaries, over 35 of which used to be pets or performers. They found that chimps that had little exposure to other chimps as infants - primarily during the first four years of life - showed reduced social competencies as adults than their peers who grew up with less human interaction.
"The results of this research suggest that future research should focus on developing the best management strategies for how to care for chimpanzees with a variety of early histories in order to meet their social needs," the authors wrote in the journal PeerJ.
Specifically, pet primates with high human exposure in life tended to engage in less social grooming with their groupmates - a critically important behavior for social bonding in chimpanzees. Surprisingly, these effects were expressed years, sometimes decades after their lives as pets and performers were over.
"One of the startling aspects of these findings is that these behavioral effects are so long-lasting," lead researcher Steve Ross said in a statement. "Chimpanzees which have found new homes in accredited zoos and good sanctuaries continue to demonstrate behavioral patterns that differentiate themselves from more appropriately-reared individuals. As a result, the process of integrating them with other chimpanzees can be challenging, stressful and even dangerous at times."
While chimps are incredibly intelligent, they are also still animals, needing interaction with other members of their species.
Currently, it is still legal to keep chimpanzees as pets in the United States, despite the fact that they are an endangered species. Ross and his colleagues hope that their research, on top of the several incidents of chimp attacks, will add to growing evidence against such practices.