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  The Mammals of Texas - Online Edition

Western Red Bat
Order Chiroptera : Family Vespertilionidae : Lasiurus blossevillii Lesson and Garnot

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.