Unmonitored releases of small animals? The importance of considering natural dispersal, health, and human habituation when releasing a territorial mammal threatened by wildlife trade

Unmonitored release is a common practice, especially in small animals, that present a series of adverse conditions if not well-planned. Small research centers and non-governmental organizations in developing countries often receive animals that are then subject to unmonitored releases. We explored the patterns of post-release and natal dispersal in the Javan slow loris, a Critically Endangered venomous and territorial mammal that is highly threatened by wildlife trade. We then determined the importance of health status and human habituation for the survival of translocated and natally dispersing animals. We collected data from 2012 to 2018 on pre-release and pre-dispersal health conditions and human habituation, post-release and post-dispersal presence of wounds, behavior, and ranging patterns of 11 translocated and 11 natally dispersing individuals and compared them with 12 stable resident individuals. Translocated animals had a larger home range size (15.9 ± 4.1 ha) and higher wound presence during recaptures (0.47 ± 0.13) than stable resident individuals (3.2 ± 3.0 ha; 0.10 ± 0.06) but they did not differ from natally dispersing individuals (13.8 ± 3.7 ha; 0.28 ± 0.11). Both translocated and natally dispersing individuals can move to a different habitat type compared to their release area or natal range. The fate of both translocated and natally dispersing individuals was influenced by their health state (p < 0.001), and human habituation significantly affected the possibility of being captured for wildlife trade of translocated individuals (p = 0.048). We highlight the importance of considering natal dispersal, health state, and human habituation before the release of small animals to avoid death and capture for wildlife trade. © 2020 Elsevier Ltd