10/12/2026
As we enter October, we would like to introduce this month’s spotlight species – bats!
This week, we will be looking at the little brown bat (Myotis lucifugus). Native to North America, these bats can be found across the northern half of the continental U.S., as well as Alaska and Canada. They are a notably small species with an average body length of 3-4 inches, and while the little brown bat’s average lifespan is typically 6-7 years, they have on occasion been recorded living as long as up to 30 years in the wild.
Like most bats, the little brown bat is nocturnal, typically roosting in caves, mines, or trees during the day and emerging to hunt for insects at night. To help them hunt, they engage in a process known as echolocation, during which they emit a series of high-frequency calls and listen to their echoes in order to determine the location of their prey. While flying, little brown bats are capable of emitting approximately 20 calls per second.
Little brown bats are typically active from mid-April to mid-October, spending the winter months in hibernation. Known for hibernating in groups, historically little brown bat colonies have consisted of anywhere from a few hundred to over 100,000 bats. However, populations have declined significantly over the years, largely due to the spread of white-nose syndrome, a fungal disease which primarily affects North American bats.
As of 2021, white-nose syndrome was responsible for a nearly 90% decline in under 10 years for several North American bat species, the little brown bat among them. As of now, the little brown bat is classified as threatened in the state of Michigan, with a state rank of critically imperiled. They are also classified as endangered in Canada, as well as by the IUCN.
Photo Credit: Close up Little Brown Bat by Jason Headley, Jason Headley , Creative Commons Attribution 4.0, https://www.fws.gov/.../close-little-brown-bat-jason-headley
