Have you ever stared into the eyes of one of these creatures while at the zoo? Perhaps you might see a smile, expressing joy or amusement. At other times, you may find a more distraught face, one that hints at a deeper problem. Moreover, you may see them acting in ways so unusual that you could immediately recognize that something is terribly wrong.
Some chimpanzees (Pan troglodytes) in captivity exhibit signs of serious mental health issues, as noted by researchers at the University of Kent in Canterbury, UK. Their preliminary findings, published in PLoS ONE, reveal that these issues persist even among socially enriched adult and adolescent chimpanzees in captivity. The socially enriched aspect would make these chimps the least likely to exhibit mental health issues, as they have sufficient exposure to other chimps to retain significant social contact.
Research into the behavior of chimpanzees as well as other great apes involves direct observation of their actions, painstakingly recording their actions and identifying them by descriptive titles. In this study, the researchers relied on published data from other studies that have noted behaviors considered to be abnormal. Some of these would be obvious signs of depression in humans, such as repetitive motions or self-injury by biting oneself. Others come across as somewhat unusual and perhaps disturbing, rarely or never observed among wild populations of chimpanzees.
While the amount of abnormal behavior varied between each of the chimpanzees included in this study, all of these chimpanzees had exhibited at least one of these abnormal behaviors. As these behaviors are endemic across chimpanzees in captivity, questions are raised regarding the welfare of these creatures in such enclosed settings. The researchers also note that because chimpanzees have a great capacity for sentience, emotion and suffering, they are also able to exhibit mental health issues along the same lines as humans.
Furthermore, the researchers mentioned some key characteristics of enclosures that can minimize the mental health burden that captivity places on chimpanzees. From randomized feeding schedules to socially conducive environments, there are many factors that can help simulate a more wilderness setting. Still, captivity itself will always present limits a chimpanzee will inevitably recognize, and much has yet to be discovered about how their minds can cope with such a constraint.
-Ian Yu, Science & Technology Editor