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  The Mammals of Texas - Online Edition

California Myotis
Order Chiroptera : Family Vespertilionidae : Myotis californicus (Audobon and Bachman)

Description. A small Myotis with small foot, short forearm, and relatively long tail; ears proportionately large, extending slightly beyond snout when laid forward; ratio of foot to tibia 37 to 46, usually 43 to 46; ratio of tail to head and body 91 to 98; pelage full, long, and dull; profile of skull rises sharply to the forehead and decidedly flat-topped cranium; upperparts ochraceous tawny. Most easily confused with M. ciliolabrum but differs in smaller thumb (thumb and wrist together 6-7.5 mm instead of 8-8.5 mm); smaller teeth; profile of skull abruptly, rather than gradually, rising to forehead; brain case broader. Dental formula: I 2/3, C 1/1, Pm 3/3, M 3/3 X 2 = 38. External measurements average: total length, 78 mm; tail, 37 mm; foot, 5.5 mm; ear, 13 mm; forearm, 32 mm. Weight, 3-5 g.

Species distribution mapDistribution in Texas. A western species known in Texas from the Trans-Pecos region and one disjunct record from the Panhandle (Randall County). This is one of the few species that winters in the Trans-Pecos, where it is found in desert, grassland, and wooded habitats.

Habits. These small bats are inhabitants of wooded canyons, open deciduous and coniferous forests, and brushy hillsides. Their daytime roosts are in crevices in the tops or sides of shallow caves, in cliffs and cavities, and in houses. They do not form the compact clusters typical of many other Myotis, but roost in small colonies of 1-25 individuals. These bats seem to use buildings more frequently than other Myotis. They appear on the wing much later in the evening than most species of Myotis.

Specific food items are unknown, but this bat appears to feed primarily on small moths and beetles that occur between, within, or below the vegetative canopy. Their flight is relatively slow, fluttery, and highly erratic.

They winter in at least part of their summer range, where they hibernate in houses or caves. They are fairly active in winter and winter records are relatively abundant from the southwestern United States. In summer, these bats seem quite transient and will use any suitable and immediately available site for shelter.

The single young is probably born in May, June or July. Pregnancy records vary from April 29 to July 6.