Visitors’ Effects on the Welfare of Animals in the Zoo: A Review

Davey, Gareth.  Visitors’ Effects on the Welfare of Animals in the Zoo: A Review, Journal of Applied Animal Welfare Science, 10:2, 169-183, 2007.


Gareth Davey’s journal article entitled, “Visitors’ Effects on the Welfare of Animals in the Zoo: A Review,” recounts several decades’ worth of animal welfare studies which collectively suggest that human presence at zoo exhibits has some influence on the nonhuman animals housed at zoo exhibits.  The purpose of Davey’s article is to summarize the findings of the aforementioned research in an effort to reach the conclusion that humans do influence nonhuman animal behaviors to which Davey then discusses limitations of studies thus far and possible ways of overcoming these limitations.  Early research was primarily focused on monkeys and observations from multiple studies suggest that human presence results in less social behaviors, heightened intragroup aggressive behaviors, and affected locomotor behavior and spatial dispersion.  Early research tells us that humans influence zoo animals to a much greater extent than was previously thought.  But not all species of animals react negatively to human presence.  Animals are complex and it is difficult to measure physiological responses to stress.  It is also difficult to determine causality. Increased animal behavior in some cases causes increased human density. While most research suggests that visitors have a negative or stressful impact on animals, some studies suggest that human presence and interaction may be a source of environmental enrichment.  Some animals are motivated to interact with visitors and visitors may provide a source of variety and therefore may enrich the lives of captive nonhuman animals.  Other studies suggest that naturalistic exhibit design may reduce the visitor effect and thereby increase animal welfare.  Hiding places, camouflage netting, physical barriers, and even one-way viewing mirrors may reduce the impact that visitors have on zoo animals. And still other studies suggest that some animals, like golden-bellied mangabeys respond differently to different kinds of people. They reactions varied by whether the person was a keeper or a visitor. And if the person was a visitor of the same sex, they reacted the most aggressively. Other studies found that smaller prey animals tend to exhibit more stress than larger animals like gorillas or orangutans.  Furthermore, Davey proposes that the quality of research studies can be improved to gain a clearer picture surrounding the factors influencing animal behavior.  A wider range of animal groupings should be studied, more precise measurements of stress should be employed, previously overlooked variables in prior research should be acknowledged and addressed, and an increased focus on visitor activities and proximity to the animals should be addressed rather than simply focusing on visitor density.  Overall, Davey concludes that more research is needed but the field has made several important strides in addressing animal welfare of captive animals.

Main points, potential applications, future research

  • Animals are complex so it is difficult to demonstrate causality.
  • Researchers should study more than one or two variables
  • Better statistical methods and analyses are needed
  • Involve zoo staff and designers of zoos to maximize animal welfare
  • Larger sample sizes should be used when possible
  • Absolute numbers of visitors should be used versus vague categories (large vs. small visitor presence)
  • Scientific research fields should work together and pool research findings (sociology, psychology, political scientists, etc.)

Summary by Zachary Parsons

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