58 
PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
Description. — The spot¬ 
ted bat (Fig. 11) has the most 
striking appearance of any 
species of bat in the United 
States. It has extremely large, 
pale ears (the largest of any 
North American bat) and three 
large white spots on a blackish- 
colored dorsum, one over each 
shoulder and one over the rump. 
The spotted bat is also a relative¬ 
ly large bat. Mean body mass of 
36 males and 25 females from 
multiple locations in nine U.S. 
states, Canada and Mexico, aver¬ 
aged 15.3 grams in both sexes, 
but mean forearm length of 
females (52.1 ±1.4 SD millime¬ 
ters, range 49.7-55.0) was signif¬ 
icantly larger than that of the 
males (50.1 ±1.9 millimeters, 
range 43.9-53.1; (Best, 1988). 
Distribution and Systematics. — Spotted bats occur in the western United States, Canada, 
and Mexico (Fig. 12). In the United States, they can be found in parts of Arizona, California, Col¬ 
orado, Idaho, Montana, Nevada, New Mexico, Oregon, Texas, Utah, Washington, and Wyoming. 
Within these states they are very patchily distributed but are often found where cliffs that provide 
crevices for roosting are within flight distance (for example, Easterla, 1970, 1973; Poche, 1981; 
Fenton et al., 1987; Wai-Ping and Fenton, 1989; Storz, 1995; Perry et al., 1997; Pierson and Rainey, 
1998b; Priday and Luce, 1999; Rodhouse et ah, 2005). The scientific name of the spotted bat was 
first used in 1894 by Allen (1893). No subspecies are recognized. Watkins (1977) provided a tax¬ 
onomic synonymy of past scientific names applied to the spotted bat. The generic name Euderma 
is a combination of two Latin words meaning “good” or “beautiful” and “skin”, and the specific 
epithet stems from the Latin word meaning “spotted”. Other English common names include pinto 
bat and black-and-white pinto bat; a Spanish common name is murcielago pinto. 
Habitats and Relative Abundance. — Spotted bats have been captured in many western 
U.S. habitat types at elevations ranging from 104 to 3,230 meters (Reynolds, 1981; Pierson and 
Rainey, 1998b). Dominant vegetation co mm unities at capture sites include Mojave, Chihuahuan, 
and Sonoran deserts, Great Basin sagebrush, pinon-juniper woodlands, oak savannas, ponderosa 
pine, mixed conifer, and spruce-fir forests (for example, Benson, 1954; Easterla, 1965,1970,1973; 
Poche and Baillie, 1974; Bleich and Pauli, 1988; Berna, 1990; Geluso, 2000; Chambers et ah, 
2011). Although these bats are widespread, distributions are discontinuous and patchy, and the 
species can be relatively uncommon compared to many other species of bats. This bat was at one 
time so poorly known that C. Hart Merriam wrote in 1899 “that it was among the rarest mammals 
in the world” (Vorhies, 1935:225). 
Fenton et ah (1987) surveyed for both echolocation and audible calls of these bats at 1,186 
study sites grouped into 80 areas where the species had been previously reported or thought to 
occur. Sites were distributed from southern British Columbia to the U.S.-Mexico border. They 
Figure 11 . Spotted bat, Euderma maculatum (photo by J. Scott Alten- 
bach). 
