Foods and Habitats of Aquatic Snakes (Reptilia, Serpentes) in a Louisiana Swamp

The foods and habitats of seven species of aquatic snakes were investigated in a Louisiana swamp, the Atchafalaya River Basin. Nerodia rhombifera was the most abundant species, and N. cyclopion, the second most common species, was an ecological associate. Stomachs of 796 aquatic snakes were examined. N. rhombifera and N. cyclopion fed mainly upon fish, and Agkistrodon piscivorus fed upon fish and other vertebrates. Catfish were frequently ingested by N. rhombifera, and A. piscivorus, but rarely by N. cyclopion. N. fasciata showed preferences for anurans and fish, and N. erythrogaster for anurans. Regina grahami and R. rigida fed upon crayfish. N. rhombifera and N. fasciata were observed utilizing crayfish burrows, and individuals of all seven aquatic species occasionally moved considerable distances overland. In the ecosystem under consideration, N. rhombifera and N. cyclopion are habitat generalists and food specialists; A. piscivorus is a habitat specialist and probably a food generalist.