Rebloggable by request.
Stereotypic Movements in Zoo Animals
Stress and Adaptation. Toward Ecologically Relevant Animal Models
It should be noted that while some abnormal behaviors can be induced by their environment, that is not always the case. “Not all animals develop abnormal behavior in response to compromised welfare, and some types of stereotypic behavior cannot be linked to poor environmental conditions” (Jacobsen et al. 2010; Mason and Latham 2004)
In fact, when investigating the influences of cage size and novelty on two groups of captive galagos, Dr. Leanne Nash found that exploration, social sniffing, and nonsocial activity was heightened when in the novel cage size (1986). This occured for the group that experienced an increase in cage size as well as the group that experienced a contraction in cage size.
Now this isn’t saying that the environment doesn’t play a role in development and/or prevention of abnormal behaviors, just that it doesn’t play the absolute role.
Rearing history has been suggested as a major indicator of abnormal behavior in nonhuman primates. Nursery / peer-reared macaques display more abnormal behavior than macaques that were mother-reared (Bellanca 2002). And in the same study, locomotor stereotypy (fancy name for a repetitive purposeless motion like pacing, swaying, rocking, etc) was positively correlated with the amount of time the subjects were singly housed during their first 48 months of life (Bellanca 2002).
Regardless of rearing history, it is the job of the behaviorists, technicians, zoo keepers, and caretakers to provide the best environment possible for the animals in their charge. Encouraging a wide range of species typical behavior promotes the psychological well being of animals in captivity (Jacobsen 2010; Animal Welfare Act). Social housing with compatible partner(s) is thought to be the best form of enrichment, as it allows for a more natural expression of behavior (grooming, dominance hierarchies, affiliative behavior, etc), although foraging tasks and manipulable objects have also been demonstrated as successful enrichment methods in addition to social housing.
My point is, that animal behavior - especially abnormal behavior - is a complicated subject. Not every animal you see pacing at a zoo has a mental disorder. But if they were not mother raised, lack conspecifics, and do not have an environment that encourages them to express natural behaviors, they certainly are in danger of developing a mental disorder. I understand that this is different from the human definition, where in a mental disorder is often times associated with genetics, but as an animal behaviorist I can assure you that these learned disorders can be just as detrimental to the animals who suffer from them.
Bellanca, Rita U., and Carolyn M. Crockett. “Factors predicting increased incidence of abnormal behavior in male pigtailed macaques.” American Journal of Primatology 58.2 (2002): 57-69.
Jacobsen, Kirsten R., L. F. Mikkelsen, and J. Hau. “The effect of environmental enrichment on the behavior of captive tufted capuchin monkeys (Cebus apella).”Lab animal 39.9 (2010): 269-277.
Lutz, Corrine K., and Melinda A. Novak. “Environmental enrichment for nonhuman primates: theory and application.” Ilar Journal 46.2 (2005): 178-191.
Nash, Leanne T., and Shawn‐Marie Chilton. “Space or novelty?: Effects of altered cage size on Galago behavior.” American Journal of Primatology 10.1 (1986): 37-49.
Mason, G. J., and N. R. Latham. “Can’t stop, won’t stop: is stereotypy a reliable animal welfare indicator?.” Animal Welfare 13.Supplement 1 (2004): 57-69.
****Side note: This is generally all from a primate perspective on enrichment since I am an animal behaviorist for primates. Also, I tried to put links to PDFs with my citations, but if they don’t work then send me a message and I’ll get you the article. Sorry if I soapbox’d a bit there, preventing and treating abnormal behaviors is pretty much my life right now so I tend to go on about the subject. If you have any questions about this or any other primatology / ethology subject then I’d be happy to look into it for you!