Hoary Bat
Last Update/Review: June 17, 2002
The
hoary bat (Lasiurus cinereus) is the largest bat found in
Alberta (Figure 7). Adults may weigh up to 35 gm (1.2 oz) and have
a wingspan of 40 cm (16 in). Their long narrow wings provide a strong,
powerful, and rapid flight. The body and inter femoral flight membranes
are covered with thick dark brown or black hair. Many of the individual
hairs are tipped with white, giving a "frosted" or "hoary" appearance.
The frosted coat may provide camouflage by making the bat look like
lichen or a withered leaf on tree bark.
Hoary bats are solitary individuals which roost in areas of forest cover. During the day, they are concealed among the leaves or on the bark three to four metres (10-12 ft) above the ground. One female in Wisconsin returned to the same spot on a spruce branch at least three years in a row. Hoary bats appear to prefer evergreen trees, and could live throughout the boreal forest zone of Alberta. The bats leave the trees after dark to feed on nocturnal flying insects, often high above the canopy.
Hoary bats are distributed widely throughout North, South, and Central America and are one of the most widespread of mammals. They are the only wild land mammal to naturally colonize the Hawaiian Islands. As they raise their young throughout Canada and the northern United States, but winter in the southern United States and Mexico, they must undertake long migrations in the spring and fall. Males apparently spend the summer in the western United States. Females migrate farther than males; most of the hoary bats found in Alberta are females or females with young. Each female bears two young in late June. The juveniles stay in the tree while the female forages for food.
