Crazy animals: what captivity does to wild monkeys, elephants and giraffes in zoos
Stereotypical behavior in an animal is any unnatural repeated action that is done in response to boredom, stress or general unhappiness. It can involve pacing back and forth, swaying from side to side, or even mutilation or self-harm (Van Tuyl 13). Because mentally insane humans exhibit similar behavior, some individuals have gone so far as to say animals acting in such a way may also be mentally unsound.
There are many things that drive animals to perform stereotypical behavior. Among these is the housing of animals in small confined spaces that prevent them from free movement or exercise. Zoos around the world give captive lions 18,000 times less roaming space than is used by their wild counterparts (14). Therefore, it should come as no surprise that an Oxford University study calculated that lions in zoos spend almost half of their time pacing back and forth, aimlessly (13).
However, this may be more than just a response to inadequate room. It may also be because of their inability to hunt and capture their prey, a pursuit which keeps them challenged and occupied in the wild. Supplying captive animals with ready-made meals denies them a chance to express their instincts and engage in the complex task of finding food. As a consequence, they become bored and restless.
Further, humans cannot always provide animals with their unique dietary requirements. An imbalance of nutrients may cause deficiencies or excess and result in several problems. Zebras in zoos are often overweight because the grass they are fed is far more energy rich than grasses from the African savannah (13). A scientist who studied wild gorillas extensively with Diane Fossey claimed to have never seen one vomit, and further, never to have heard of anyone else who had (13-14). The Captive Animals’ Protection Society has filmed footage of gorillas housed in zoos not only vomiting, but afterwards eating the regurgitated food (13).
Animals may be housed with few companions for various reasons, including limited resources. They can form bonds with co-inhabitants that are later transferred elsewhere to relieve overpopulation. Therefore, some social animals are denied the companionship and diversity of interaction they require. Animals that favor seclusion are similarly unhappy, displayed daily for the benefit of prying eyes. One zoo conducted a study of gorillas’ behavior and found that the gorillas showed an increase in agitated rocking, aggression, and grooming when closely observed by large crowds (16).
While none of these problems can be completely resolved, some zoos do take measures to provide their animals with a more natural existence. However, space is among the most limited of resources and will continue to be problematic. There is simply no practical way to expand the space of lion enclosures 18,000 times or the space of polar bear enclosures 1 million times, as is considered representative of their normal range (14). As a consequence, animals will remain in smaller environments than are ideal.
However, zoos do what they can to prolong food seeking and gathering behavior, which normally consumes most of the animals’ daily existence. To do this, food may be scattered around an enclosure instead of placed in front of an animal. Sometimes it is even hidden or concealed in a box or bag (22). This provides more of a challenge and animals must engage in several attempts to successfully gain access to each meal. The food itself may also be given in a form that requires work, such as an unshelled coconut or fully leaved branch (22) . These require slow and methodical processing.
Nutritionists are on staff at zoos to provide animals with balanced meals. However, whether meals are actually correctly balanced is limited by human knowledge. The gorillas mentioned earlier may in fact be regurgitating their food because they are not receiving a necessary staple in their diet or are forced to eat unusual food combinations. As the Philadelphia Zoo website states, feeding monkeys unique varieties of foods is a concept about which they are “still learning” (20). Their enrichment programs focus a great deal on “creating variety” during feedings. Unfortunately, it is possible that some combinations are less than ideal.
Further, resources are a problem. Although zebras do eat grass, they eat a specific type that has a different composition from grasses found on non-African continents. This cannot be easily corrected as it is impractical to grow a field of African plant life within a zoo enclosure for a variety of reasons. In addition to climate and seasonal differences, the introduction of foreign plants is controlled in the interest of protecting native species from cross contamination or extinction.
Some zoos ensure that social animals are housed in group settings. Similarly, they separate animals that are naturally alone or that fight upon contact in the wild. They may even design safe hiding places for species that prefer to remain elusive (20). However, since the point of the zoo is to display animals to the public, there will always be a human presence, as well as a way to see into enclosures. They may be allowed the opportunity to hide and escape from human “predators,” but it must still be stressful to animals to be constantly surrounded by them.
Zoos can and have taken steps to improve the situations in which animals are housed. But there is only so much they can do. Animals will likely continue to have limited movement, social interaction, food sources, and foraging opportunities. Perhaps for these reasons, worldwide studies have found that zoo's elephants engage in abnormal behavior twenty-two percent of the time and bears pace agitatedly back and forth for thirty percent of the time (90). Chimpanzees taken from zoos and placed in sanctuaries were observed to have performed such excessive stereotypical behavior that their hands were covered in scar tissue from chronic gnawing (90). Improvements to zoos are therefore necessary for the sake of the animals.
Unfortunately, they will always fall short of what should be provided by nature.
Zoos and Animal Welfare
Christine Van Tuyl, Book Editor
Christine Nasso, Publisher
Elizabeth Des Chenes, Managing Editor
Farmington Hills, MI: Gale Cengage Learning, 2008.