Sex Ratios of the Big Brown Bat, Eptesicus fuscus, at an Urban-Rural Interface


  • Jason P. Damm Environmental Solutions & Innovations, Inc.
  • Dale W. Sparks Environmental Solutions & Innovations, Inc.
  • John O. Whitaker, Jr. Indiana State University


Wildlife responds to urbanization in a variety of ways. Some species, including the big brown bat (Eptesicus fuscus), take advantage of anthropogenic landscapes and can thrive in association with humans. The species is often found in association with humans, and is known to exploit urban environments. Females of many bat species, including the big brown bat, are sexually segregated during summer when females roost communally and males individually. The purpose of this study was to examine if there is gender bias in the distribution of this otherwise ubiquitous species across an urban/rural interface associated with conservation lands owned by the Indianapolis International Airport. Using a long-term data set, we compared sex ratios of big brown bats captured from a rural area south of Interstate 70 to the more urbanized northern region north of Interstate 70. Both areas were dominated by female big brown bats, but a greater proportion of males were captured in the rural area.