ESR 18:279-289 (2012)  -  DOI: https://doi.org/10.3354/esr00454

Non-invasive evaluation of physiological stress hormone responses in a captive population of the greater bilby Macrotis lagotis

Edward Narayan1,*, Jean-Marc Hero1, Nicole Evans1, Vere Nicolson2, Al Mucci2

1Environmental Futures Centre, School of Environment, Griffith University, Gold Coast campus, Queensland 4222, Australia
2Dreamworld, Coomera, 4209 Queensland, Australia

ABSTRACT: Captive breeding programs are increasingly being used as a management option for threatened mammals. The greater bilby Macrotis lagotis, for example, is a vulnerable species which is maintained in captivity at several facilities in Australia. Non-invasive evaluation of stress hormones (cortisol in mammals) via excretory metabolites can be used to monitor physiological stress responses of captive individuals. In this study, we validated an enzyme-immunoassay (EIA) to measure cortisol metabolites in fresh faecal samples of adult male and female bilbies (n = 7) held in captivity at the Dreamworld Theme Park, Queensland, Australia. The faecal cortisol EIA was validated via parallelism and the recovery of exogenous cortisol added to pooled faecal extracts (>99% recovery). Female bilbies had higher average faecal cortisol metabolite concentrations and higher day-to-day variation than male bilbies; however, there was no relationship with bilby age. Cortisol metabolites for most individuals varied widely through time, with numerous peaks and troughs in response to long-term stressors (illnesses, injury and reproductive issues) and short-term stressors, such as use in shows at Dreamworld or public displays in local schools, manual restraint and short-term veterinary procedures (e.g. general anaesthesia). Overall, the higher mean cortisol metabolite concentrations of individuals suffering long-term stress was related to a greater response to short-term stressors. This suggests an interaction between responses to short-term and long-term stressors which is perhaps due to habituation and/or facilitation of long-term stressors. Non-invasive faecal monitoring of stress hormones could provide further information on the implications of captive breeding programs and the release of animals reared in captivity.


KEY WORDS: Macrotis lagotis · Captive breeding · Capture · Reintroduction · Stressor · Health


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Cite this article as: Narayan E, Hero JM, Evans N, Nicolson V, Mucci A (2012) Non-invasive evaluation of physiological stress hormone responses in a captive population of the greater bilby Macrotis lagotis. Endang Species Res 18:279-289. https://doi.org/10.3354/esr00454

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