Short-chain carboxylic acids in the scent gland secretions of the eastern small-scaled burrowing asp (Atractaspis fallax: Lamprophiidae, Serpentes, Reptilia)

Abstract

Embedded in the tail base of all snakes is a pair of scent glands that open through ducts at the margin of the cloaca. Scent gland secretions (SGS), which typically are discharged when snakes are disturbed, are thought to deter predators. Previous chemical analyses have indicated carboxylic acids as the chief lipid constituents of SGS. We examined by GC-MS the SGS of the eastern small-scaled burrowing asp (Atractaspis fallax), a venomous, fossorial species in the Lamprophiidae, a diverse family containing more than 60 genera of mostly non-venomous African snakes. Our results confirm that acetic, propionic, 2-methylpropanoic, n-butanoic, and 3-methylbutanoic acids are the major constituents in the SGS samples of A. fallax. These compounds are widespread in the SGS of the Alethinophidia (‘typical snakes’). Some of these short-chain acids also occur in the anal glands of mammals and the uropygial (preen) glands of birds, where they arise via microbial activity. Whether these compounds in SGS have a similar origin is unknown.