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Once Bitten, Twice Shy: Does Previous Experience Influence Behavioural Decisions of Snakes in Encounters with Predators?


  • Patrick T. Gregory

    Corresponding author
    1. Durrell Institute of Conservation and Ecology, University of Kent, Canterbury, UK
    • Department of Biology, University of Victoria, Victoria, BC, Canada
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Patrick T. Gregory, Department of Biology, University of Victoria, PO Box 3020 STN CSC, Victoria, BC, Canada V8W 3N5.



Injuries are common in animals of diverse taxa and are usually attributed to encounters with predators. Although often non-lethal, injuries nevertheless represent effects of predators that can have negative consequences for demography and fitness (e.g. reproductive costs). However, encounters with predators also represent experience through which animals can learn and positively adapt their future behaviour, potentially mitigating, at least partly, the negative effects of prior exposure to predators. I predicted that injured grass snakes (Natrix natrix), which presumably had been handled previously by a predator, would be more likely to move before capture than uninjured snakes. This prediction was borne out. Snakes with injuries also had lower body condition than uninjured snakes, although the effect was non-significant. Snakes that had been previously captured also were significantly more likely to move before capture than snakes that had never been caught before. These results provide strong evidence for the role of experience and learning in modifying the antipredator behaviour of snakes.