What is known and what is not yet known about deflection of the point of a predator's attack

Deflection occurs in predator-prey interactions where prey possess traits that influence the position of the predator's initial contact with the prey's body in a way that enhances the prey's probability of survival when attacked. As an anti-predatory defence occurring late in the sequence of an attack, deflection is an understudied but fascinating strategy that involves a range of unusual adaptations in diverse prey species. Deflective traits have been postulated to be important to the defensive strategies of a range of organisms, but although evidence for their existence is variable among groups, we argue that previous research neglects some promising taxa. As a defence, deflection will probably play a crucial role in the behavioural ecology and evolution of both prey species and their predators; as such, it warrants greater interest from zoologists. Here, we first summarize what is known about deflection from the current literature. We next offer predictions about the co-evolutionary possibilities surrounding deflection, based on the benefits and costs experienced by prey and their predators. Finally, we outline the most interesting outstanding avenues for future research in the field of deflection and make new suggestions as to how they could be explored usefully.