Relaxed predation theory: size, sex and brains matter

Edwards, Megan C. and Hoy, Julia M. and FitzGibbon, Sean I. and Murray, Peter J. ORCID: (2021) Relaxed predation theory: size, sex and brains matter. Biological Reviews, 96 (1). pp. 153-161. ISSN 1464-7931


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 naive 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.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 07 Mar 2021 23:44
Last Modified: 23 Jun 2021 07:32
Uncontrolled Keywords: naivety, predator recognition, conservation, prey naivety, introduced predators, predation, predation pressure, marsupial
Fields of Research (2008): 06 Biological Sciences > 0603 Evolutionary Biology > 060303 Biological Adaptation
06 Biological Sciences > 0602 Ecology > 060201 Behavioural Ecology
Fields of Research (2020): 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310301 Behavioural ecology
31 BIOLOGICAL SCIENCES > 3104 Evolutionary biology > 310403 Biological adaptation
Socio-Economic Objectives (2008): D Environment > 96 Environment > 9608 Flora, Fauna and Biodiversity > 960899 Flora, Fauna and Biodiversity of Environments not elsewhere classified
Socio-Economic Objectives (2020): 18 ENVIRONMENTAL MANAGEMENT > 1806 Terrestrial systems and management > 180606 Terrestrial biodiversity
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