Exploring body injuries in the horseshoe whip snake, <em>Hemorrhois hippocrepis</em>

Abstract

Body injuries on snakes may serve as indices of predation rate, which is otherwise difficult to record by direct methods because of the usual scarcity and shy nature of these reptiles. We studied the incidence of body scarring and tail breakage in a Mediterranean colubrid, Hemorrhois hippocrepis, from south-eastern Spain. This species exhibits two traits that favour tail breakage, a long tail and active foraging tactics. The large sample (n = 328) of individuals acquired also enabled us to determine how the incidence of these injuries varies ontogenetically, between the sexes, in relation to energy stores, and to seek for the possible existence of multiple tail breakage. Overall, the incidence of tail breakage was rather low (13.1%) and similar to that of body scarring (12.7%). However, there was a significant ontogenetic shift in the incidence of tail breakage; such injuries barely appeared in immature snakes but stub-tailed individuals were present in 38.7% of snakes in the upper decile of body size. In contrast to most other studies, our data show a sex difference in the incidence of these injuries, adult male rates quadrupling those of adult females for body scarring and males maintaining larger stubs, probably because of the presence of copulatory organs housed in the base of the tail. Larger individuals did not have shorter tail stubs, a finding that does not support the multiple-tail-breakage hypothesis. Our results also fail to support the idea of a cost of tail breakage or body scarring in terms of body condition.