Image of big brown bat hanging from cave roof

Bats are known as warm weather creatures, but did you know that they can be active throughout the winter? Biologists at the Montana Natural Heritage Program along with a coalition of partners have been monitoring bats year-round and have recorded their echolocations during some of the year’s coldest months.

The MSU Library’s new Acoustic Atlas received this January 4th, 2013 recording of a Big Brown Bat near the Continental Divide on the Big Hole River in southwest Montana. The original recording was above the range of human hearing, but was slowed down by 70% to make it audible.

Click here to listen to bat recordings on SoundCloud


Very little is known about bat behavior during the winter. Bats are much less energetic this time of year, but some species like the Big Brown Bat and Western Small-footed Myotis are known to venture out in search of water and may even be foraging during portions of the winter as well.

Biologists are monitoring bats in Montana to increase their understanding of both winter and summer roosts and baseline activities during typical hibernation periods. They hope to understand the health of Montana’s bat populations and assess potential threats such as white-nose syndrome. That disease has not yet reached Montana, but is devastating bat populations across North America.

Visit the Acoustic Atlas to hear the sounds of a wide range of animal species from Montana and the Western United States.