The genus Lasiurus is found in North America, South America, and the Hawaiian Islands. Lasiurus cinereus ranges from British Columbia to southern South America. [Osgood] (1943: 53) records two subspecies from Chile.
Information on the natural history of the hoary bat is meager. It was observed in the Kettle River Mountains, but none was obtained. It flew erratically and rapidly and did not appear until darkness had set in. At least two were seen above a road through a forest of western larch and ponderosa pine. Probably it breeds in the mountains of northeastern Washington and in the northern Cascades.
The hoary bat is migratory, leaving the state in August and September, rarely lingering until early October. It winters along the coast of central and southern California ([Dalquest], 1943: 23).
Antrozous pallidus cantwelli [Bailey]
Pallid bat
Antrozous pallidus cantwelli [Bailey], N. Amer. Fauna, 55:391, August 29, 1936.
Type.—Obtained at Rogersburg, Asotin County, Washington, by G. G. Cantwell on May 28, 1918; type in United States National Museum.
Measurements.—A male from the south bank of the Columbia River, opposite Fallbridge, Klickitat County, measures: total length 113; length of tail 40; hind foot 14; ear 36; height of tragus 13; weight 19.8 grams.
Distribution.—Recorded only from localities near the Columbia and Snake rivers in eastern Washington; from Wenatchee (W.W.D.) south and east to Bly and Rogersburg ([Taylor] and [Shaw], 1929: 9).
Description.—Antrozous pallidus is more likely to be confused with Corynorhinus than with any other kind of bat and can be distinguished from Corynorhinus by its larger size (4-1/2 to 5 inches), lighter color, thick and leathery membranes, and shorter, wider ears. Antrozous lacks the prominent "lumps" on the rostrum, characteristic of the long-eared bat. The dental formula is: i. 1-1/2-2, c. 1-1/1-1, p. 1-1/2-2, m. 3-3/3-3 = 28.