Little Brown Bat
Little brown bats make their summer home in the Caledonia Mine, near Ontonagon.

Tracking the Travels of Little Brown Bats

by Jennifer Donovan

They’re tiny creatures with chocolate-brown hair, out-sized ears, and wings. They gobble mosquitoes and other insect pests during the summer and hibernate in caves and mines when the weather turns cold. They are little brown bats, and a deadly disease called white-nose syndrome is threatening their very existence.

A novel technique using stable hydrogen isotopes—a kind of chemical fingerprint found in tissues such as hair—is enabling researchers at Michigan Technological University to determine where hibernating bats spend their summers. Up to now, stable hydrogen isotopes have been used mostly to track migratory birds.

Knowing the migration patterns of the bats could help predict and ultimately manage the spread of white-nose syndrome. The disease hasn’t hit the bats of the Upper Peninsula yet, but it is wiping out entire bat populations in the northeastern US and moving west.

Learn more about bats and the scientists’ efforts to save them at