The Herpetological Journal

pp.67-70

Authors: Massimo Capula , Luca Luiselli , Lorenzo Rugiero, Fatima Evangelisti , Claudio Anibaldi And Ve Ronica Trujillo Jesus

Abstract: The food habits of Coluber hippocrepis nigrescens, a colubrid snake endemic to the island of Pantelleria in the southern Mediterranean Sea, were studied by means of both stomach contents and faecal analyses. Snakes preyed only on vertebrates, and most of the prey eaten were rodents (especially Rattus norvegicus). Ingested biomass per snake averaged 55.63±48.94 g (range: 8 - 131 g), i.e. about 28.5 % of the average snake mass (195.18 ±65.61 g; range: 39-277 g). Log prey mass and log predator mass were positively correlated. The prey mass to predator mass ratio was not significantly correlated with log predator mass. 3 6.36% of the prey found in C. hippocrepis stomachs was eaten by snakes when it was already carrion, as demonstrated by the presence of abundant flesh-fly larvae in rats regurgitated by snakes. This is a very unusual foraging mode for snakes, which are known as active predators feeding on live organisms. We hypothesize that this unusual foraging mode is an adaptive strategy depending on (I) low level of food availability and (2) high abundance of dead prey, on this arid Mediterranean island.