Site familiarity affects antipredator behavior of the amphisbaenian Blanuscinereus

Morphological adaptations of amphisbaenians to fossorial life might affect their antipredator-behavior decisions. Amphisbaenians exposed on the soil s urface by a predator can escape by burrowing immediately or by using altern ative defensive behaviors on the soil surface, and should decide where to b urrow in order to return to their home range. We simulated in the laborator y predatory attacks toward individual amphisbaenians (Blanus cinereus), and examined whether their antipredator and burrowing responses were affected by site familiarity (familiar versus unfamiliar substrate) and their intern al state (i.e., body temperature and associated burrowing performance). Amp hisbaenians showed significantly longer episodes of alternative antipredato r behaviors on the soil surface (coiling and still) when the temperature wa s low. Before starting to burrow in unfamiliar substrates, individuals emit ted numerous tongue flicks and moved for significantly longer periods of ti me than when on familiar substrates, independently of temperature. In contr ast, in their own cages, with familiar substrates, amphisbaenians performed only a few tongue flicks before starting to burrow. Subsequently, the time spent burrowing was significantly longer when the temperature was low or a mphisbaenians were on an unfamiliar substrate. These results suggest that a mphisbaenians are able to recognize their own home range by chemosensory cu es and that they are able to use this information when deciding where to bu rrow to escape from potential predators.