Duration of immobility in salamanders, genus Plethodon (Caudata: Plethodontidae)

Immobility is a potentially important antipredator behavior in salamanders, especially for those posessing noxious skin secretions. The duration of immobility in 15 species of terrestrial salamanders (Plethodon) varied among species. Most salamanders (78.8%) became immobile when initially contacted under field conditions, and remained immobile from 1-180 s. Immobility duration was inversely correlated with substrate temperature and covaried with air temperature, but snout-vent level (SVL) had no effect on duration. Only immobility times of Plethodon shenandoah were significantly different from any other species. Substrate temperature, air temperature, SVL, and species accounted for only a small percentage of the variance (r²=0.09). The degree of disturbance received during a predator-prey encounter is probably more important than the subtle effects of temperature and SVL in determining immobility duration.