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Animal profile

Little Brown Bat

Myotis lucifugus

MammaliaForest and wetland edges in summer; caves and mines with stable cool humid air for winter hibernationEndangered

Field profile

The little brown bat was for decades one of the most abundant mammals in northern North America, weighing about 7 to 14 grams. It hunts small flying insects over water and forest edge and hibernates communally in caves and mines. Populations in the northeast collapsed after 2006 with the arrival of white-nose syndrome.

Scope note

This is an editorial profile, not a diagnostic field-identification guide or a substitute for current conservation assessments. Follow the cited sources on each fact for the evidence trail.

Published field notes

2023-11-24

Little Brown Bat

A cold-loving fungus emptied northeastern bat caves

White-nose syndrome is caused by a fungus that grows on hibernating bats at cave temperatures. It does not poison them so much as wake them, and the repeated arousals burn the fat reserve that was meant to last until spring.

Read with evidence →

Little Brown Bat | Daily Animal Facts