Post-Cranial Hairs in Four Families of Bats

Abstract

This study identifies the presence of specialized post-cranial hairs on 66 species of bats, and speculates on their significance. While examining museum bat specimens, three main suspected sensory types of hair were discovered: toe hairs, rump hairs, and uropatagial hairs. Life history traits such as day roost type, size of roosting group, and diet were compared with the presence or absence of these hairs using Spearman's Rho tests. The presence of post-cranial hairs was extremely variable across families and genera, making their function difficult to infer. Nevertheless, our tests revealed statistically significant correlations between the presence of uropatagial hairs and using small roosts and the presence of rump hairs and using hollow tree roosts. We suggest that rump hairs may play an important role in roost navigation, while uropatagial hairs may contribute to landing or foraging abilities, especially when found on tailless bats. Toe hairs are suspected to aid in grooming. Histological analysis and further behavioral data are needed to ascertain the functional role of these post-cranial hairs.