Hoary bats give birth to their young while hanging upside down in the leafy shelter of their daytime retreat. The newborn's skin is brown, darker on the body than on the wings, and lighter beneath. The throat and head are much paler and their feet are nearly black. Fine, silver-gray hair covers their dorsal area. The hoary bat's ears and eyes are closed at birth and open on days three and twelve, respectively.
Purposeful flight is possible for the infants by the thirty third day.
Behavior Hoary bats are solitary. They roost 3 to 5 m above ground during the day, usually in the foliage of trees. They prefer dense leaf coverage above and an open area below. They also prefer trees that border clearings. They have been seen roosting in a woodpecker hole in British Columbia, in the nest of a gray squirrel, and under a driftwood plank.