The population size of the southern bent-winged bat, a critically endangered bat subspecies, has significantly declined in the last 50 years. As part of a larger study to determine whether disease could be a contributing factor to this decline, morphometric data was gathered for southern bent-winged bats and compared with the more common eastern bent-winged bats. Southern bent-winged bats were heavier, but forearm length was not significantly different between the two subspecies. This suggests that southern bent-winged bats may require more energy to fly and forage than eastern bent-winged bats. Consequently, southern bent-winged bats may need to consume more food on a daily basis, potentially increasing their susceptibility to adverse conditions such as drought.