Relaxed predation theory: size, sex and brains matter.

Australia's wildlife is being considerably impacted by introduced mammalian predators such as cats (Felis catus), dogs (Canis lupus familiaris), and foxes (Vulpes vulpes). This is often attributed to native wildlife being naïve to these introduced predators. A systematic review of the literature reveals that native metatherians (body mass range 0.02-25 kg) do not recognise, and show relaxed antipredator behaviours towards, native and some introduced mammalian predators. Native eutherians (all with body mass < 2 kg), however, do appear to recognise and exhibit antipredator behaviours towards both native and introduced predators. Based on our findings, we propose a novel theory, the 'Relaxed Predation Theory'. Our new theory is based on the absence of large mammalian predators leading to reduced predation pressure in Australia during the past 40000-50000 years, and on three key differences between Australian metatherians and eutherians: size, sex, and brains. In light of this Relaxed Predation Theory, we make a number of recommendations for the conservation of Australian wildlife: (i) predator avoidance training of suitable species; (ii) exclusion fencing to exclude some, but not all, predators to facilitate the development of antipredator behaviours; (iii) captive breeding programs to prevent the extinction of some species; and (iv) reintroduction of Australia's larger predators, potentially to compete with and displace introduced predators. A more detailed understanding of the responses of Australian mammals to predators will hopefully contribute to the improved conservation of susceptible species.

Microchips for macropods: First use of a microchip-automated door by a bridled nailtail wallaby (Onychogalea fraenata).

Commercially available microchip-automated devices for companion animals also have potential application with captive wildlife. To explore this potential, a captive bridled nailtail wallaby was trained to use a SureFlap Microchip Pet Door. Throughout the 62 day study the wallaby's interactions with the door increased in frequency and intensity, culminating in the repeated use of the microchip-automated door. This was the first record of any captive macropod being trained to use a microchip-automated device and demonstrates proof-of-concept that captive macropods can successfully utilize commercially available microchip-automated devices. Further research is recommended to develop methodology and evaluation techniques for training captive macropods while also exploring intra- and inter-species variations in responses.

The potential for microchip-automated technology to improve enrichment practices.

The greatest limitation involved with providing enrichment and evaluating its effects on captive mammals is a lack of available staff time [Hoy et al., 2009]. One method to overcome this is through the use of automated husbandry systems to dispense enrichment to individual animals by using implantable radio frequency microchips. An international multi-institutional survey was conducted to determine whether the personnel involved with management, research, and husbandry of captive mammals would support the development of such automated husbandry systems. The survey was also designed to establish which applications of the system would be considered to be most beneficial. Overall, there was a very high level of interest by survey respondents in adopting automated husbandry systems and all potential applications were considered beneficial to varying degrees. These results, together with the relatively low cost of installation and operation, demonstrate that in the future automated enrichment could be an important and effective means of enhancing captive animal management.

Thirty years later: enrichment practices for captive mammals.

Environmental enrichment of captive mammals has been steadily evolving over the past thirty years. For this process to continue, it is first necessary to define current enrichment practices and then identify the factors that limit enhancing the quality and quantity of enrichment, as well as the evaluation of its effectiveness. With the objective of obtaining this information, an international multi-institutional questionnaire survey was conducted with individuals working with zoo-housed mammals. Results of the survey showed that regardless of how important different types of enrichment were perceived to be, if providing them was particularly time-consuming, they were not made available to captive mammals as frequently as those requiring less staff time and effort. The groups of mammals provided with enrichment most frequently received it on average fewer than four times per day, resulting in less than two hours per day spent by each animal care staff member on tasks related to enrichment. The time required for staff to complete other husbandry tasks was the factor most limiting the implementation and evaluation of enrichment. The majority of survey respondents agreed that they would provide more enrichment and carry out more evaluation of enrichment if it was manageable to do so. The results of this study support the need for greater quantity, variety, frequency, and evaluation of enrichment provided to captive mammals housed in zoos without impinging on available staff time.