Studies have identified at least 29 tree species used by Indiana bats during the summer and during spring and fall migrations. Since so many tree species are used as roosts, tree species is likely not a limiting habitat requirement. In addition to trees, Indiana bats have used a Pennsylvania church attic, a utility pole, and bat boxes as roosts. However, use of man-made structures appears to be rare. Roost selection by females may be related to environmental factors, especially weather. Cool temperatures can slow fetal development, so choosing roosts with appropriate conditions is essential for reproductive success and probably influences roost choice.