||The Mammals of Texas -
Chiroptera : Family
Vespertilionidae : Myotis californicus (Audobon
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.
Distribution 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
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.