Analysis of Captive African (Loxodonta africana) and Asian (Elephas maximus) Elephant Fecal Glucocorticoid Concentrations when Compared Among Several Environmental, Management, and Health Factors.
Year: 2016
Type: article
Abstract: Identifying links between environmental, management, and health factors as they relate to physiological stress in captive elephants is crucial for the improvement of husbandry and welfare practices in North American zoos.Non-invasive fecal glucocorticoid protocols have been implemented as successful methods to examine the effects of short term and chronic elevations of cortisol in small groups of elephants; but no others have examined fecal glucocorticoids on a large scale.The study population consisted of 130 African (Loxodonta africana) and 104 Asian (Elephas maximus) elephants living within 65 different facilities across North America.Fecal samples were collected every other week over the course of 12 months and analyzed for glucocorticoid concentration.These metabolites were obtained through the use of a corticosterone enzyme-linked immunosorbent assay (ELISA).Elephant data for sex, environmental (season and climate zone), management (space experience, enrichment diversity, feed total, herd size, animal contact, and social group factors), and health factor (foot and joint scores) also were obtained through various direct and survey methods.Repeated measures analysis of fecal glucocorticoid concentrations showed significant main effects on fecal glucocorticoids for the African elephant population.Sex, feed total (number of feedings per day), and social group count were all significant predictors of fecal glucocorticoid levels (P<0.05); while animal contact during the day tended towards significance (P=0.0605).Female African elephants exhibited higher average glucocorticoid concentrations when compared to male African elephants.Increased glucocorticoid levels were positively correlated with increasing the feed count, as well as, the greater number of social groups an African elephant experienced within a zoo.Also, African elephants experienced a decrease in glucocorticoid concentrations related to an increase in the number of animals they have contact with during the daytime.These results were not replicated in the Asian elephant population.The Asian population showed only a single significant effect on fecal glucocorticoid concentrations.They exhibited seasonal fluctuations in glucocorticoid levels.The average glucocorticoid concentrations were higher in the Spring season in comparison to the other seasons (P=0.0411).Analyses showed a significant interaction effect between season and climate zone in relation to fecal glucocorticoids in Asian elephants (P=0.0102).These results suggest that environmental, management, and health variables are all important potential sources of stress in the captive environment, which could have an effect on elephant welfare.This research reports species specific differences in how elephants cope and adapt to their housing conditions that are not yet known and need to be further investigated to ensure their survivability in both captivity and the wild.
Author: Jessica D. Bray
Language: English
Subfield: Animal Science and Zoology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2761659196