38 
PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
tips of the hair on the venter 
(Jones, 1977). Hairs on the feet 
extend beyond the tips of the toes 
in Rafmesque’s big-eared bat but 
not in Townsend’s big-eared bat 
(Sealander and Heidt, 1990). 
Adult body mass of Townsend’s 
big-eared bats ranges from five 
to 13 grams; females may aver¬ 
age slightly larger than males, 
and reportedly reach heavier 
body mass in autumn and winter 
(as summarized by Kunz and 
Martin, 1982; Ingersoll et al., 
2010). The calcar is not keeled. 
This species often curls its ears 
backwards in a manner resembling ram’s horns when hibernating or torpid. 
Distribution and Systematics. — Five recognized subspecies of Townsend’s big-eared bat 
occur within the U.S. (Handley, 1959; Kunz and Martin, 1982). Two isolated subspecies in the east¬ 
ern and central U.S. were listed as Endangered under the U.S. Endangered Species Act in 1979 
(U.S. Fish and Wildlife Service, 1979): the Virginia big-eared bat occurs in parts of West Virginia, 
Virginia, Kentucky, and North Carolina; the Ozark big-eared bat is found or historically occurred 
in restricted l im estone areas of adjacent portions of Arkansas, Oklahoma, Missouri, and Kansas. 
The isolated distributions of the Ozark big-eared bat and Virginia big-eared bat were thought to be 
relicts of post-Pleistocene climates (Humphrey and Kunz, 1976), but more recent genetic analysis 
suggests a much older divergence (Piaggio and Perkins, 2005; Lack and Van Den Bussche, 2009). 
Overall, the remaining three U.S. subspecies are found across the western and west-central 
states (Fig. 10). The subspecies distributions described by Handley (1959) and provided in 
the range descriptions in the 1994 designation of federal Category 2 candidates (U.S. Fish and 
Wildlife Service, 1994) have changed based on modern phylogenetic analysis (Piaggio and 
Perkins, 2005; Smith et al., 2008; Lack and Van Den Bussche, 2009; Piaggio et al., 2009). 
C. townsendii townsendii occurs in the lower 48 states from the Pacific coast east to southern 
Montana, western South Dakota, western Colorado, and western New Mexico; C. townsendii 
pallescens occurs from western Colorado and northeastern Arizona eastward through south-central 
Wyoming to western Kansas, western Oklahoma, and northwestern Texas; C. townsendii australis 
is found in western Texas, southern New Mexico, and Mexico (see Lack and Van Den Bussche 
2009 for map; Tipps 2012). These three subspecies are not practical to distinguish in the field (Pier¬ 
son et al., 1999). 
Improved knowledge about systematic relationships of the bats in the big-eared bat subgroup 
(including Corynorhinus, Euderma, Idionycteris, and Plecotus) within the family Vespertilionidae 
have resulted in changes in nomenclature within the past 25 years. These changes have caused 
some confusion for the non-specialist. As summarized by Tumlinson and Douglas (1992) and Bog- 
danowicz et al. (1998), the names Corynorhinus and Idionycteris are now the generally accepted 
generic names for U.S. bats formerly grouped under the genus Plecotus (including the species pre¬ 
viously known as Plecotus townsendii, Plecotus rafinesquii, and Plecotus phyllotis ). The generic 
name Plecotus remains valid only for certain species of Old World bats. Previous nomenclature 
was largely based on morphological studies that were concluded in the 1950’s (Handley, 1959), 
Figure 9. Townsend’s big-eared bat, Corynorhinus townsendii (photo by J. 
Scott Altenbach). 
