While zoos claim that welfare needs in zoos are effectively met, the behavior of captive great apes tells us a different story. The high prevalence of stereotypies in zoo-housed primates points to chronic stress and inability to cope with their captive situation.
Stereotypies are baseless, repetitive behaviors that serve no functional purpose and point to mental distress. Behaviors such as self-mutilation, food-based stereotypies (such as regurgitation and reingestion), pacing, rocking, digit sucking, self-grasping, and extreme and/or inappropriate aggression or submission, are examples. Some of these behaviors are described as “natural” by zoos since they are commonly observed in a zoo environment, but this is misleading as these behaviors are uncommon – or undocumented – in the wild.
Captive Great Apes Commonly Display Signs of Psychological Distress
Research suggests that “a substantial number of great apes in captivity show behavioral abnormalities and measurable signs of distress.” One survey of 108 zoos found that 40% of great apes exhibited some form of abnormal behavior.1 In the most extreme cases, pharmacological treatments are used in attempts to treat captivity-related mental illness, with increasing use of anti-depressants within the zoo industry.
In the late 1990s, the Head Veterinarian of Franklin Park Zoo in Boston, MA, Dr. Hayley Murphy, and Psychiatrist, Matthew Mufson, surveyed zoos with gorillas to better understand their use of psychopharmaceuticals. Half of the 31 zoos that responded to the query confirmed that they had employed psychopharmaceuticals for their gorillas.
A Tragic Example of Mental Distress
A tragic example of the extent to which mental health issues can impact captive apes is that of Kitombe (Kit), a gorilla who arrived at Franklin Park Zoo in 1998 at the age of 12. He quickly impregnated one of the females, Kiki. Over time, Kit’s behavior became increasingly violent with a particular focus on a female gorilla called Gigi. He attacked her multiple times, causing her serious injury.
In an attempt to curb Kit’s aggression, zoo staff experimented with various anti-depressants and anti-psychotic drugs. When one did not work, he was weaned off and put on another. In total, he was put on four different drugs, none of which had a significant impact.
In the meantime, his attacks on Gigi continued with news reports stating that she became “a nervous wreck.” She was given a combination of drugs to calm her, but it was not until Kit was permanently removed from the group that she began to improve.
Kit was put in solitary confinement, where he stayed for ten lonely years.
When Kit passed away at the zoo in 2024, news reports made no reference to his sad and violent past, instead calling him a gentle father and mate.
We Should Have Empathy for Our Fellow Primates
As fellow primates, it should not be surprising to us that great apes suffer mentally and emotionally when held captive for their lifetimes in inadequate and stressful situations. And, as fellow primates, it is our responsibility to bring an end to the ongoing exploitation of these animals in zoos to prevent this unnecessary suffering by rejecting their ongoing captivity for our entertainment.
To learn more about the plight of great apes in zoos, check out our report, Our Captive Cousins.
Keep Wildlife in the Wild,
Liz
1 Bollen KS, Novak MA. A survey of abnormal behavior in captive zoo primates. Am J Primatol. 2000;51:47.
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