Stress – the condition keepers and animal husbandry professionals most want to avoid for the animals in their care. Psychosocial and environmental stress can have significant effects not just on day to day mood and demeanor, but also on the immune system, reproduction, and life span. Caretakers have the duty to monitor and alleviate stress if possible. It is critical, therefore, that they are able to recognize when an animal is stressed so steps can be taken to minimize the stress as soon as possible.
However, when considering animals housed in groups, those whose interactions with humans are limited, or native populations of animals in the wild, it can quickly become difficult to determine what level of a particular behavior is normal and what constitutes a stress induced behavior. As an example, let us consider compulsive hair plucking. In humans, trichotillomania is definitively linked to chronic stress and is diagnosed primarily in women and adolescent girls. Hair plucking behavior is also observed in other primate species, but the line between normal grooming behavior and that which is linked to stress must be established. Earlier in 2016 researchers studied hair plucking behavior in a group of bonobos, an endangered great ape, at the Columbus Zoo and Aquarium.1 Incidences of grooming and hair plucking were observed and recorded over a 128 hour period, and urine samples were collected and analyzed for cortisol. Brand et al. were able to establish a significant positive correlation between self directed hair plucking and urinary cortisol levels, measured using our DetectX® Cortisol EIA kit (K003) amongst female bonobos but not the males.
The correlation of the observational data with measurements of cortisol allows researchers to definitively link this hair plucking behavior with stress levels. In the future, increases in hair plucking behavior can be noted as a possible sign of increasing stress levels and investigated accordingly.
Observational data will always be the most abundant data available for animals, be they captive or wild populations. But the reasons behind the behaviors we observed can be elusive. Being able, through research, to tie observed behaviors to measured fluctuations in hormones related to stress or reproductive state can provide a great deal of insight into what those behaviors might represent and what, if anything, might be able to be done to alleviate them.
1) Brand et al (2016) Hair plucking, stress and urinary cortisol among captive bonobos (Pan paniscus); Zoo Biology, epub ahead of print
*For additional cortisol kit citations, scroll to the bottom of the product page
Corticosterone CLIA Kit, K014-C
Cortisone EIA Kit, K017-H
Cortisone CLIA Kit, K017-C
Urinary Creatinine Detection Kit, K002