Responses by canids to scent gland secretions of the western diamondback rattlesnake (Crotalus atrox)

Abstract

Many snakes discharge malodorous fluids from paired scent glands in the base of the tail when they are disturbed. A number of authors suggest that these secretions repel predators. Scent gland secretions of the western diamondback rattlesnake (Crotalus atrox), or dichloromethane extracts of them, were presented to coyotes (Canis latrans) in three field tests, and to domestic dogs (Canis familiaris) in two kennel tests, to determine whether responses of possible benefit to snakes are elicited. Free-ranging coyotes visited and rubbed and rolled at stations containing scent gland secretions in perforated plastic capsules more frequently than at those containing untreated or dichloromethane-treated capsules. Responses to dichloromethane extracts of scent gland secretions subjected to rotary evaporation were not significantly different from those to dichloromethane. Pure and mixed breeds of dogs presented with filter papers treated with dichloromethane or a dichloromethane extract of scent gland secretions mouthed (licked, bit, or ate) secretion-treated papers more frequently. Staffordshire terriers presented with filter papers treated with dichloromethane or dichloromethane extracts of snake scent gland and alligator (Alligator mississippiensis) paracloacal gland secretions exhibited urination postures to snake secretion-treated papers more frequently than to dichloromethane-treated papers, but responses to snake- and alligator-treated papers did not differ significantly. There was no indication that canids are repelled by scent gland secretions.