Antipredator mechanisms of Australian frogs

Abstract

We examined the antipredator mechanisms of 19 Australian hylid species (two genera) and 23 myobatrachid species (nine genera). Frogs of 39 of the 42 species exhibited one or more defensive mechanisms (other than escape), including postures, bright coloration, adhesive skin secretions, and/or calls. Defensive posturing occurred in individuals of 38 species, and varied in relationship to morphology and localization of skin glands. Bright colors, when present, typically were displayed during defensive postures. We documented dramatic geographic variation in the antipredator display of one species, Limnodynates tasmaniensis. Defensive postures were accompanied by secretions from dorsal skin glands. These secretions were sometimes associated with a distinctive odor. Adhesive skin secretions were present in burrowing frogs of three genera. Defensive calls were emitted by most hylids but none of the myobatrachids. We offer a hypothesis of mimicry to explain the behavior pattern of exposing the bold black and white ventral surface in Pseudophryne and Crinia species.