Male-male ritualized combat in the Brazilian rainbow boa, Epicrates cenchria crassus

摘要

MALE-male combat is a ritualized behaviour occurring mainly during the mating season (Greene, 1997; Schuett, 1997; Schuett etal., 2001) which is widespread among snake families including Boidae, Elapidae, Viperidae and Colubridae (Shine, 1978, 1994). Male-male combat is an example of intrasexual selection in which males compete for access to females. Typically, the two opponents attempt to physically subdue one another by exerting pressures (e.g., pushing, flipping, entwining) on the anterior part of their body in an attempt to bring their adversary to the ground. (Carpenter, 1977). Among boid snakes male-male combat is recorded in only one erycinae (Eryx colubrinus - see Schuett et al., 2001), 21 pythoninae (see Shine, 1994; Schuett et al., 2001) and 14 boinae species - nine of these being Neotropical (see Shine, 1994; Schuett et al., 2001). The genus Epicrates includes ten species and combat is recorded for six, including the Brazilian E. c. cenchria (Shine, 1994; Schuett & Schuett, 1995; Schuett et al., 2001). Despite the existence of many records in boid snakes, detailed descriptions of combat behaviour are only available for the pythoninae (Python molurus ; Baker et al., 1979) and the boinae Sanzinia madagascariensis.