O’SHEA, CRYAN & BOGAN: UNITED STATES BAT SPECIES OF CONCERN 
83 
State Designations: Arizona Game and Fish Department (2012): Tier IB Species of Greatest 
Conservation Need. California Department of Fish and Wildlife (2015b, 2017): Special Animals 
List, Species of Special Concern. Nevada Department of Wildlife (2013): Sensitive Mammal, 
Species of Conservation Priority. Nevada Department of Conservation and Natural Resources 
(2015a): Imperiled. 
Description. — The Cali¬ 
fornia leaf-nosed bat (Fig. 19) is 
a medium-sized bat with an erect 
nose leaf, large ears, and large 
eyes. Unlike the three other leaf¬ 
nosed bats that regularly enter 
the lower southwestern U.S., the 
snout and tongue are short. The 
pelage appears gray, but the basal 
two-thirds of the hairs are white, 
with the upper third yellowish 
brown (Bradshaw 1961). Fore¬ 
arm lengths range 45 to 51 mil¬ 
limeters and body masses range 
9.7 to 17.0 grams (Bradshaw, 
1961). 
Distribution and System- 
atics.— This bat is the most 
northerly representative of the 
Family Phyllostomidae, the New 
World leaf-nosed bats, a group with over 140 species that is largely Neotropical in distribution. 
Unlike many other insectivorous bats of the U.S., the California leaf-nosed bat does not enter daily 
or seasonal cycles of torpor and is thus limited to warm regions and warm microclimates (Bell et 
al., 1986; see below). Currently there are two species recognized in the genus Macrotus. M. cali- 
fornicus is found in the deserts of southern California, southern Nevada, and southern Arizona in 
the U.S., southward through Baja California, most of Sonora, and northern Sinaloa, Mexico (Fig. 
20); M. waterhousii occurs in tropical areas of southern and central Mexico and in islands of the 
Caribbean Sea. 
Earlier literature can be confusing and may sometimes refer to populations of M. californicus 
in the southwestern U.S. as M. waterhousii californicus (if published at a time when only a single 
species with subspecies was recognized), whereas prior to the mid-1960s three species of Macro¬ 
tus were thought to exist (Anderson and Nelson, 1965). Careful chromosomal, electrophoretic, and 
morphologic analysis showed that M. californicus is a species distinct from M. waterhousii (Davis 
and Baker, 1974; Greenbaum and Baker, 1976). Earlier taxonomic synonymies can be found in 
Grinnell (1918), Anderson and Nelson (1965), Anderson (1969), and Hall (1981). No subspecies 
of the California leaf-nosed bat are currently recognized. Macrotus is derived from Greek words 
meaning “long” and “ear”. The specific epithet is based on geography. Other common names 
include California big-eared bat and Californian leaf-nosed bat. 
Habitats and Relative Abundance.— California leaf-nosed bats are usually found in low 
desert habitats below about 1,100 meters (Bradshaw, 1961). Individuals do not range widely. The 
documented maximum distance for movement from a winter roost to a maternity colony was 93 
kilometers, and the longest movement of any kind was 137 kilometers; the majority of recaptures 
Figure 19. California leaf-nosed bat, Macrotus californicus (photo by J. 
Scott Altenbach). 
