Researchers from the Lincoln Park Zoo have found that chimpanzees that were raised by humans, particularly in the critical first four years of their lives have difficulties later on as adults socializing with other chimps. It was observed that this lack of social skills among their own species could last even decades after they are released from their lives as pets or performers.
The study was led by Stephen R. Ross, PhD., the administrator for the Chimpanzee Species Survival Plan and director at the Lincoln Park Zoo's Fisher Center for the Study and Conservation of Apes. His team surveyed and observed the behaviors of 60 chimpanzees with various personal histories living at different parks and sanctuaries across the United States. In the study, 36 of the chimps were former entertainers or pets living in private homes.
While most would agree that chimpanzees are better off amongst their own kind rather than with humans, the process of re-integrating them into primate society is more complicated than it seems.
The team found that those raised and trained by humans were often separated from their mothers and families within the first 24 hours of their lives. The 14 month long study showed that, among other normal chimpanzee behavior, these chimps lacked interest in social grooming among other chimps, which is an essential part of interaction among primates.
Grooming is how apes bond in daily life. A chimp that is uninterested in or unable to participate in social grooming is like a human who does not reciprocate a friendly handshake. Unable to groom another chimp could be taken as a sign of hostility in the group and may cause problems for a former pet trying to reintegrate into life with their own species.
"Chimpanzees are incredibly intelligent and sensitive animals. 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," he said regarding the findings the research team published in PeerJ.
Animal rights groups may have the best intentions in advocating removing chimps from private homes and back into sanctuaries or the wild; however, often times, they do not consider the long-term implications for chimps who may have never had any interaction with their own species for most of their lives.
Chimpanzees that are kept as pets often become too big and aggressive for their human families to care for properly, and often times, they can turn violent and deadly.
According to Dr. Ross, one of the goals of the study was to address the needs of the chimps to be with their own kind and to push for legislation to keep them out of private homes as pets, which is still legal in many States.
