Prolactin and substrate stimulation of locomotor activity in adult tiger salamanders (Ambystoma tigrinum)

Abstract

Groups of adult tiger salamanders were treated with either prolactin or saline and were maintained between behavioral observation on either a moist pea gravel substrate or in water. During 60‐minute observation periods, all animals in a group were placed together in moisture‐gradient apparati, and locomotor activity scores and substrate preferences were recorded and analyzed. Prolactin or saline and substrate type exerted no effects on eventual substrate preference. However, animals in both substrate groups treated with prolactin displayed greater activity than either group treated with saline. The group of salamanders treated with prolactin and held between behavioral observations on moist gravel displayed significantly more activity than animals in any other group. These results suggest that prolactin‐stimulated locomotion represents a behavioral component of a “second metamorphosis” event in tiger salamanders.