Diet of Thamnodynastes strigatus (Serpentes, Colubridae) in southern Brazil

Abstract

We analyzed the gut content of 151 specimens of the colubrid snake Thamnodynastes strigatus from the state of Rio Grande do Sul, southern Brazil. The recorded prey items were anurans (66%; n = 33), fish (28,0%; n = 14), mammals (4,0%; n = 2), and reptiles (2,0%; n = 1). There was no correlation between the snout-vent length (SVL) of the snakes and the total length (TL) of their prey, but the correlation between the snake SVL and the ratio prey TL / snake SVL was significant and negative. This negative correlation evidences that T. strigatus does not exclude proportionally small prey items of their diet, and that, proportionally, the biggest prey items are ingested by the smallest snakes. Relatively large prey items are manipulated before ingestion and oriented headfirst, whereas relatively small prey were swallowed head- or tail- first.