|The Mammals of Texas -
Western Red Bat
Chiroptera : Family
Vespertilionidae : Lasiurus blossevillii Lesson
Description. A medium sized bat
similar in appearance to the eastern red bat (Lasiurus borealis). Pelage coloration
is rusty red to brownish and lacks the white-tipped hairs
which gives the frosted appearance so characteristic of L.
borealis. The posterior one-third of the interfemoral
membrane is bare or only sparsely haired. L.
blossevillii is slightly smaller than L. borealis
and most cranial measurements (greatest length of skull,
zygomatic breadth, mastoid breadth, and length of
maxillary toothrow) are significantly smaller. Dental
formula: I 1/3, C 1/1, Pm 2/2, M 3/3 X 2 = 32. External
measurements average: total length, 103 mm; tail, 49 mm;
foot, 10 mm; ear from notch, 13 mm; forearm, 40 mm.
Distribution in Texas. Across
the southwestern and far western areas of the United
States south into Mexico and Central America. Known in
Texas from only one specimen captured in the Sierra Vieja
in Presidio County of the Trans-Pecos. Additional
specimens are to be looked for in this region, a
potential area of overlap between this bat and L. borealis.
Habits. Western red bats appear
to prefer riparian areas where they roost in tree
foliage. In New Mexico and Arizona this bat is
occasionally captured in riparian habitats dominated by
cottonwoods, oaks, sycamores, and walnuts and is rarely
found in desert habitats. In Mexico, this bat has been
captured in riparian, xeric thorn scrub and pine-oak
forests of the San Carlos Mountains, only 160 km south of
the Texas border. The Texas specimen was captured over
permanent water in desert scrub habitat.
This bat appears to be migratory in the
southwestern United States. Specimens from Arizona, New
Mexico, and the Texas specimen are all from summer. A
winter withdrawal from this region to Mexico is likely.
The food habits and reproductive
biology of this bat are poorly known. Females pregnant
with three fetuses have been captured, and pregnant bats
from New Mexico have been caught from mid-May to late
June. L. blossevillii may raise as many as three
young annually with parturition occurring in mid-May
through late June.