Prey defences: mechanisms, evolution and ecology

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SOME prey animals hide from predators. Some run away. Still others counterattack. This research investigates evolutionary and ecological processes leading to variation in prey defences, and the influence of prey defences on an animal's social behaviour, parental care and ecological patterns.   I will address the question of why some animals appear to altruistically defend individuals that are not their own offspring against predators. Even though examples of selfless behaviour are common in the animal world, we do not expect such behaviour to arise through natural selection. Through previous work with mule deer (a seemingly altruistic animal that defends fawns from another species!), I ruled out the possibility that females defend non-offspring because they mistake them for their own, and the common idea that females only help close relatives so as to pass on their shared genes. I will now test the hypothesis that the defence of non-offspring is a spillover of a female's motivation to defend her own fawn. A rigid response to any distress call may ensure a female defends her own fawn when it is in need, even if it has the drawback of leading her to defend many other animals.   In another line of research, I will observe natural encounters between predators and prey (coyotes, deer, and two species of ground squirrels) in a prairie landscape to determine how the behaviour and density of prey animals affect a predator's hunting success and its decision to hunt one species of prey rather than another.   This research will advance our understanding of the evolution of prey defences and intertwined patterns of social behaviour and parental care. It will also provide insight into the way the behaviour of individual prey and predators shapes survival patterns of prey. This research is applicable to conservation. It will increase our understanding of the way coyotes affect native prey species on Canada's native prairie grassland, a habitat supporting a disproportionate share of endangered species.