Hoary Bat

Lasiurus cinereous

Hoary bats are the most widespread of all bats in the United States. Though not yet recorded in Alaska, these bats are thought to occur in all 50 states. Hoary bats are solitary. They roost 10-16 feet above ground during the day, usually in the foliage of trees. Hoary bats reach their peak activity at about five hours after sunset, although they may occasionally be seen flying on warm winter afternoons. Their flight is strong and direct, reaching speeds of thirteen miles per hour. While hunting, they soar and glide.

Family:

Vespertilionidae (evening bats and vesper bats)

Description:

The hoary bat averages 5.1 to 5.7 inches long with a 15.5 inch wingspan and a weight of about 0.92 oz. About the size of a fat mouse. These bats have blunt, rounded noses and small, beady eyes. Its coat is dense and dark brown, with white tips to the hairs that give the species its “hoary” appearance for which it is named. The body is covered in fur except for the undersides of the wings. Males and females are dimorphic in body mass, with females 40% heavier than males.

Habitat:

Authorities disagree as to the bat's preference for coniferous versus broadleaf trees. Hoary bats are thought to prefer trees at the edge of clearings, but have been found in trees in heavy forests, open wooded glades, and shade trees along urban streets and in city parks.

Range:

They range from the tree limit in Canada down to at least Guatemala in Central America, and throughout South America. They are the only bats found in Hawaii.

They are abundant in California, Arizona, and New Mexico, where they winter. They winter in southern California.

Diet:

Moths make up the bulk of the diet of hoary bats. These bats are also known to feed on flies, beetles, small wasps, grasshoppers, termites, and dragonflies.

Breeding:

Copulation is followed by delayed fertilization, a process in which the sperm is stored in the female reproductive tract all winter and is available to fertilize the egg when ovulation takes place in the spring. They appear to give birth from the middle of May into early July. Little is known about the bat's gestation time. Litter size is usually two, but can range from one to four.

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