The ability of Mexican free-tailed bat mothers and pups to recognize vocalizations of their presumptive kin (pup isolation calls and mother echolocation calls, respectively) was tested using playbacks of recorded calls. Captive individuals were presented with calls of two bats, one presumptive kin and the other a stranger, from opposite sides of a circular wire arena. Response was determined by amount of time spent on each side of the arena, time spent in contact with a cloth bat model in front of each speaker, and number of separate contacts with each model. For the latter two measures, mothers showed a significant preference for the calls of their presumptive pups. Pups were attracted to adult echolocation calls, but did not show preference for calls of different mothers. The ages of pups appears to have had no effect on the responsiveness of either pups or mothers to the playbacks. This study demonstrates vocal kin recognition by mothers, and suggests an important role for acoustic cues in mother-pup reunions in this species. The findings do not preclude the possibility that vocal recognition of mothers by pups also occurs
