THERMAL ECOLOGY OF MOUSTACHED AND GHOST-FACED BATS (MORMOOPIDAE) IN VENEZUELA

The moustached bats, Pteronotus davyi, P. personatus, and P. parnellii, and the ghost-faced bat, Mormoops megalophylla (Mormoopidae), are homeotherms with normal to slightly low basal rates of metabolism for mammals of their body mass. They are unable to resist temperatures below 15-degrees-C for long, and none of the four species studied appears able to enter torpor. Thermal conductance of each species is high compared to expected values for mammals, but within the upper range of available values for bats. Except in P. personatus, adult females have lower basal rates of metabolism than conspecific males. We hypothesize that this sexual difference in basal rate of metabolism is related to the different thermal conditions at roost sites for each sex and that roost temperature is an important selective force in the evolution of thermoregulatory patterns and basal rate of metabolism in bats.