There is considerable variation in habitat. M. vivesi shelters under piles of stones along seashores or in sea caves and fissures and forages over the open sea. M. hasseltii also is reported to forage over the ocean, and sometimes to roost in adjacent mangroves. Caves are a more common roosting site for Myotis, but hollow trees, rock crevices, and structures erected by people also are often used by some species. M. formosus has been found hanging in trees, bushes, and tall jungle grass.
All species roost by day and forage at night.
The feeding flights usually alternate with periods of rest, during which the bats hang to digest their catch. The flight is described as slow and straight in M. myotis and erratic and faster in some other species. Roosting sites sometimes change by season, and it is common in North American species for maternity colonies to break up in the fall and shift to hibernacula. This species, like many others found in temperate regions, is known to hibernate during the winter. M. sodalis concentrates in caves during the fall, preliminary to winter hibernation, but disperses to other habitats for the summer.