Avoiding the serpent's tooth: predator-prey interactions between free-ranging sidewinder rattlesnakes and desert kangaroo rats

Many species perform complex antipredator displays that deter attacks by informing predators that continued attempts at prey capture will be costly. However, because of the difficulties in studying the behaviour of free-ranging predators, we have a limited understanding of how predators respond to those signals. Here, we took advantage of our ability to quantify predatory behaviours of free-ranging sidewinder rattlesnakes, Crotalus cerastes, to examine the influence of anti-snake behaviours performed by desert kangaroo rats, Dipodomys deserti. We recorded natural encounters and quantified the predator-deterrent behaviours displayed by the kangaroo rats, as well as any strikes performed by the rattlesnakes and whether the strikes were successful. We found that predator-deterrent signalling significantly reduced the probability that a rattlesnake would strike. This was most likely due to the ability of kangaroo rats to mobilize extremely rapid evasive leaps; even rats that appeared unaware of the snakes were almost always able to avoid rattlesnake strikes. The degree of effectiveness of this evasive leaping in countering rattlesnake predation was unexpected and indicates that this may be a rich system for exploring the biomechanics of extreme physical performance in a naturalistic context.