To run or hide?: escape behaviour in a cryptic African snake

Abstract

Optimal escape theory predicts that escape behaviour of an organism is best  understood in terms of costs and benefits of escaping relative to risk of predation. However, risk of predation facing an organism is dependent on various biotic and abiotic factors. In order to better understand escape behaviour of an African snake, the Namaqua dwarf adder (Bitis schneideri), I simulated predatory attacks on 51 free-ranging snakes, quantifying whether or not they fled. Additionally I measured body size, sex, body condition, and the surface temperature of the location of each snake, as well as the situation (buried or active on the surface) of the snake. I used generalized logistic regression to assess which variables predicted whether the snake fled during/following the simulated attack or not. Surface temperature was significantly associated with a flight-response, with warmer snakes more likely to flee than cooler snakes. Buried snakes were less likely to flee than snakes that were active on the surface. These findings generally support optimal escape theory in that both factors are strongly linked to risk of predation: temperature is likely to influence sprint  performance, while situation is likely to influence the detectability of the snake to predators.

Key words: Bitis schneideri, Namaqua dwarf adder, Succulent Karoo, ecology.