New research suggests that chimpanzees raised by humans to be pets or performers are more likely to have behavioral problems later in life.

According to NBC News, past studies have shown that humans do not benefit from raising chimpanzees into a life of performing or to be a pet. The new study, published in the journal PeerJ, now suggests it is not good for either party.

Hani D. Freeman and Stephen R. Ross teamed up to study 60 chimpanzees living in sanctuaries or zoos. Of their study subjects, 36 were pets or performers at one point and, in their infancy, those with less interaction with other chimps were more likely to develop behavioral problems such as social grooming and other bonding practices.

"Unusually for a study on this topic, we looked at the degree of human and chimpanzee exposure on individual chimpanzees along a continuum," Ross said in a press release. "This showed that those chimpanzees with more atypical beginnings to their lives, spending much more time with humans than with their own species, tended to behave differently than those that stayed with their family through infanthood."

Ross is the founder of the Lincoln Park Zoo's Project ChimpCARE, which relocates former pet and performer chimpanzees to certified zoos and sanctuaries. In most U.S. states, chimps are legal pets, but owners often give them up later in their lives because they grow too difficult to manage.

Zoos and sanctuaries get a majority of chimpanzees that were once pets or performers. Ross said he hopes his study will help end the practice of taking chimps as pets, as they are also known to be a risk to public safety and health.

"One of the startling aspects of these findings is that these behavioral effects are so long-lasting," Ross said. "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.

"Denying them access to members of their own species, during the critical infanthood period, results in behavioral outcomes that last a lifetime. Even with the best possible care as adults, they often can't fit in with the other chimpanzees."