Den sharing behaviour of captive brushtail possums (Trichosurus vulpecula)

Abstract

Den sharing among wild brushtail possums (Trichosurus vulpecula) has important implications for disease transmission. This study investigated den sharing in captive possums, and measured interactions between possums sharing dens. Thirty‐four sexually mature possums (16 female, 18 male) were housed in single‐sex or mixed‐sex pairs in large enclosures that contained two dens. Daily patterns of den sharing were recorded for each pair over a 69 day period in the breeding or non‐breeding season. Social behaviour within shared dens was sampled using miniature infrared cameras. Male pairs rarely shared dens in the breeding or non‐breeding seasons (4% and 1% of days respectively) and usually engaged in ‘threats’ and ‘fights’ associated with den defence. Pairs of female possums (in both seasons) and mixed‐sex pairs housed together in the breeding season shared dens most frequently (between 84% and 91% of days), and also spent the most time together in dens each night. While sharing dens, affiliative interactions were frequent, including long periods of ‘touching’, and also ‘food sharing’ and ‘allogrooming’. The preference for den sharing and close contact shown by captive possums highlights the importance of den sharing as a potential route for disease transmission.