(Uploaded by Plazi for the Bat Literature Project) Radio-tracking was used to monitor day-to-day changes in feeding are day-roosting sites, and roost group composition of two species of foliage-roosting fr bats, Artibeus lituratus and Vampyrodes caraccioli. The bats changed roost sites most daily but did not move to sites closer to current feeding areas. Relatively sta groups of one male and two or three females with young used and reused seve foliage sites in areas of 0.5 to 2.5 ha and commuted to feeding areas up to 2.5 km aw Sit-and-wait predators like owls seem to be attracted to fruiting trees. The bats su pended or greatly reduced feeding passes to fruiting trees during periods of brigh moonlight, but searching and commuting flights occurred even in the brightest moo light. Predation pressure is implicated in the evolution of both foraging and roostin behaviors.