Antipredator behavior of newly metamorphosed American Toads (Bufo a. americanus), and mechanisms of hunting by eastern garter snakes (Thamnophis s. sirtalis)

TitleAntipredator behavior of newly metamorphosed American Toads (Bufo a. americanus), and mechanisms of hunting by eastern garter snakes (Thamnophis s. sirtalis)
Publication TypeJournal Article
Year of Publication1994
AuthorsHeinen JThomas
JournalHerpetologica
Volume50
Issue2
Pagination137-145
KeywordsTOADS
Abstract

The results of three experiments on behavioral mechanisms in predator-prey relations between newly metamorphosed American toads (Bufo americanus) and eastern garter snakes (Thamnophis sirtalis) are reported. Toads responded with stereotypical antipredator behavior (crouching and lowering rates of motion) to the sight of any live snake, including known toad predators (garter snakes) and non-predators (ringneck snake, Diadophis punctatus, and green snake, Opheodrys vernalis). Toads did not respond to snake odors, to a non-moving garter snake, or to an adult toad, but they responded to an adult leopard frog. Actively hunting snakes were observed, and the posture and movement of toads within 10 cm of the predator were recorded before and after contact between predator and prey. Toads that did not move and remained crouched during the sequence were less likely to be captured than those that moved and/or were upright. Tongue contacts were much more likely to lead to capture than trunk or head contacts. Hungry toads moved more frequently than non-hungry toads and were more liley to be captured by garter snakes.