Adaptation of wild-caught Tasmanian devils (Sarcophilus harrissii) to captivity: evidence from physical parameters and plasma cortisol concentrations

Abstract

This study assessed whether capture and transferral into captivity represents a significant stressor to Tasmanian devils. Four male and four female devils were captured in the wild and housed for six months in captivity in male-female pairs. Blood samples were collected for cortisol assay at capture, every 24 h for the first 4 days, and then monthly; body weight and tail width were monitored weekly. In the males, mean plasma cortisol concentrations were highest (49 ng.ml-1 ± 9.19) at the time of initial capture; cortisol concentrations declined significantly after 48 hours in captivity (9.2 ng.ml-1 ± 5.96) and did not change significantly over the months in captivity. Females exhibited a different pattern: plasma cortisol concentrations were highest (74.0 ng.ml-1 ± 3.24) in the initial sample, but mean concentrations remained elevated in samples taken at 24, 48, and 96 hours after initial capture, and did not exhibit a significant decline (to 20.65 ± 8.95 ng.ml-1) until four weeks after capture. During the first two months in captivity, the male devils lost approximately 8.7% of their original body weight, and females lost 10.6% during this same period. However body weights then rose during the rest of the experiment. These results suggest that Tasmanian devils experience elevated plasma cortisol concentrations in response to capture and transfer into captivity. However these high concentrations are not maintained during six months in captivity, suggesting that the animals are not chronically stressed.