The bat came swooping out of the darkness into researchers' nets just before 1 a.m. — a small brown female with a secret.
As the scientists untangled its tiny limbs from the fine webbing, they didn't notice anything unusual. Not until they got back to the processing station did the puzzle emerge. The bat's size was all wrong: Too small for a big brown bat, too heavy for a little brown bat.
Measuring its slim forearm and sneaking a look at its teeth, the researchers realized they had netted a big discovery in bat ecology.
They had nabbed an evening bat — a species new to Minnesota and the first such discovery in more than a century.
Researchers from the Minnesota Department of Natural Resources (DNR) and Central Lakes College caught the bat last month while studying the summer breeding habits of a different bat species.
The evening bat is typically found farther south and east, with its northern limit historically limited to central Iowa, said Rich Baker, endangered species coordinator with the DNR.
"Very rarely do we discover a new mammal in the state," Baker said.
The last time it happened, in fact, was in 1991, with the discovery of a shrew. But it's been more than a century since a new bat species has fluttered into the state, wildlife officials said.