Gainesville, Florida

University of Florida Bat Houses

The world's largest occupied bat houses hold hundreds of thousands of flying mammals.

The world’s largest occupied bat houses are located on the campus of the University of Florida. Mostly populated by the Brazilian free-tailed bat, the bat house and barn are also home to Southeastern and Evening bats.

The original colony of bats was discovered after a fire destroyed Johnson Hall in 1987. The nearly 5,000 bats who had lived there then took up residence at several campus stadium locations. Though the musky odor of the bats and rain of guano during evening games didn’t please fans, it wasn’t until Governor Bob Martinez complained of the odor while attending an athletic event at Griffin Stadium that university officials decided something had to be done.

The first bat house was constructed in 1991. The stadiums were fitted with bat excluders, which allowed the bats to leave but not to return to roost. At first try, approximately 3,000 bats were caught in cages and relocated to the newly built bat house. Most left after only a night or two. In 1995, after years of using excluders at various campus locations and a variety of techniques to get the bats to stay at the house, it was discovered that what had been a small colony of mostly males bats had switched to a large colony of mostly females. Since then, the population has continued to increase. A second structure, the bat barn, was constructed in 2010.

The current population, estimated to be 300,000 bats, consumes more than two tons of insects a night. Observers are encouraged to come on warm, calm nights to watch the 10-20 minute show as the skies cloud with bats. Viewers are warned that the bats often dip low to gather insects that have been attracted by carbon dioxide-laced exhalations … and to beware of falling urine and guano.