General Distribution
The pallid bat is known or suspected from 16 National Forests within Region 5, including the Angeles,
Cleveland, San Bernardino, and Los Padres National Forests. During 1996-1998, bat surveys were
conducted at 76 sites located throughout the four forests of southern California. These surveys were in
partnership with the Biological Resources Discipline within the U.S. Geological Survey. Pallid bats
were found at seven of the 76 sites (four sites on Los Padres National Forest, three sites on Angeles
National Forest), at elevations of 1,100–6,600 feet (335–2,012 meters) (Stephenson and Calcarone 1999).
Recent observations have occurred in the Lake Henshaw area, Santa Ysabel, and Oak Grove area.
Abandoned mines surveys in the northeastern San Bernardino Mountains failed to detect the
species. The species has not been found recently in Descanso Ranger District but could occur in
appropriate habitats (Lake Moreno, Boulder Oaks, Cibbets Flat, Descanso, etc.). Systematics
From Natureserve explorer (2002), six subspecies of Antrozous pallidus were recognized by Martin and
Schmidly (1982). A. p. pacificus: Pacific Coast Ranges of western Oregon and California south to Los
Angeles and San Bernadino counties. A. p. pallidus: east of the range of A. p. pacificus from southern
British Columbia and east of the Cascade Range throughout much of the Columbia Plateau and Great
Basin, throughout the southwestern U.S. west of central Texas, and south to western and south-central
Mexico north of the Transverse Volcanic Cordillera. A. p. bunkeri: Barber County, Kansas, south to the
western end of the Wichita Mountains in Greer County, Oklahoma. A. p. minor: southern Baja
California north through the Colorado Desert of southeastern California and southwestern Arizona, then
northward into southern Nevada. A.p. packardi: western slopes of the Sierra Madre Occidental in
southwestern Zacatecas, Jalisco, northeastern Nayarit, and southern Sonora. A. p. koopmani: several
scattered localities in Cuba. Habitat Requirements
Pallid bats are found in a variety of habitats, including rocky canyons, open farmland, scattered desert
scrub, grassland, shrubland, woodland, and mixed conifer forest (Barbour and Davis 1967, Hermanson
and O'Shea 1983, Orr 1954, Philpott 1997). Pallid bats appear to be more prevalent within edges, open
stands, particularly hardwoods, and open areas without trees (SNFPA 2001).
Pallid bats roost in rock crevices, mines, caves, tree hollows, and a variety of anthropogenic structures
(Hermanson and O'Shea 1983). Pallid bats frequently use buildings, bridges and culverts in California
(Tatarian 2001). This bat is intolerant of roosts with temperatures in excess of 104 ° F (40 ° C) (Philpott
1997). Reproduction
Pallid bats mate late October-February, but fertilization is delayed until April–June (Philpott
1997). Maternity colonies form in early April and may contain from 12 to 100 individuals (Zeiner and
others 1990). Maternity colonies form in rock crevices, buildings and in other man-made structures such
as mine tunnels.
In the southwestern United States, young are born May–June (Hermanson and O'Shea 1983). Pallid bats
usually have one to two young, with twins most common (Nagorsen and Brigham 1993, Philpott
1997). Lactation occurs from early May to mid-August. The young are weaned 6–8 weeks after birth
(Hermanson and O'Shea 1983). Females are capable of breeding in their first year, but yearling females
usually bear only one young (Nagorsen and Brigham 1993). Daily/Seasonal Activity
Time of emergence from roost sites varies seasonally (Hermanson and O'Shea 1983) but typically occurs
30–60 minutes after sunset (Zeiner and others 1990). Emergence is later in the spring and fall
(Hermanson and O'Shea 1983). Foraging is concentrated into two periods (Hermanson and O'Shea
1983). The first major activity peak occurs 90–190 minutes after sunset, and the second occurs shortly
before dawn (Zeiner and others 1990). Pallid bats may remain torpid for more than 5 hours between
foraging periods (O'Shea and Vaughn 1977).
Foraging periods are briefer during fall and activity is infrequent below 35 ° F (2 ° C) (Zeiner and others
1990). Pallid bats are known to hibernate but arouse periodically throughout the winter to forage and
drink (Philpott 1997). Diet and Foraging
Pallid bats primarily glean prey from the ground or surfaces of vegetation, but have also been observed
to take prey in flight. Prey items include large insects such as scorpions, crickets, praying mantids, and
moths (Hermanson and O'Shea 1983). These bats have also been reported to take lizards and smaller
bats in captivity (Engler 1943). Pallid bat may hover or glide momentarily while foraging, but is
described as less maneuverable than other smaller vespertilionids (Orr 1954). Territoriality/Home Range
This species is known to commute up to 2.5 miles (4
kilometers) between day roosts and foraging areas (Nagorsen and Brigham 1993). Predator-Prey Relations
Owls and snakes are known predators of pallid bats (Zeiner and others 1990). Literature Cited
Ball, L.C. 1998. Roosting behavior of pallid bats (Antrozous pallidus): Energetic and ecological
mechanisms. Reno: University of Nevada. Ph.D. disseration
Barbour, R.W.; Davis, W.H. 1969. Bats of America. Lexington: The University Press of Kentucky.
Brown, P.E.; Grinnell, A.D.; Harrison, J.B. 1978. The development of hearing in the pallid bat,
Antrozous pallidus. Journal of Comparative Physiology 126: 169-182.
Brown-Berry, Patricia. 2002. Pallid bat species report for BLM – West Mohave Planning Area.
Engler, C.H. 1943. Carnivorous activities of big brown and pallid bats. Journal of Mammalogy 24: 96-
97.
Hermanson, J.W.; O'Shea, T.J. 1983. Antrozous pallidus. Mammalian Species 213: 1-8.
Harvey, M.J.; Altenbach, J.S.; Best, T.L. 1999. Bats of the United States. Arkansas Game and Fish
Commission, Arkansas.
Martin, C.O.; Schmidly, D.J. 1982. Taxonomic review of the pallid bat, Antrozous pallidus (Le
Conte). The Museum, Texas Tech University, Special Publication 18: 1-48.
Nagorsen, D.W.; Brigham, R.M. 1993. Bats of British Columbia. Royal British Columbia Museum
Handbook. UBC Press in collaboration with the Royal British Columbia Museum.
NatureServe Explorer: An online encyclopedia of life. 2002. Version 1.6. Arlington, Virginia, USA:
NatureServe. [Online]. Available: http://www.natureserve.org/explorer/.
Orr, R.T. 1954. Natural history of the pallid bat, Antrozous pallidus. Proceedings of the California?Academy of Science 28: 165-264.
O'Shea, T.J.; Vaughan, T.A. 1977. Nocturnal and seasonal activities of the pallid bat, Antrozous
pallidus. Journal of Mammalogy 58: 269-284.
Philpott, W. 1997. Summaries of the life histories of California bat species. Unpublished
document. USDA Forest Service, Sierra National Forest, Pineridge Ranger Station.
Sierra Nevada Forest Plan Amendment. 2001. Final EIS. USDA Forest Service.
Stephenson, J.R.; Calcarone, G.M. 1999. Southern California mountains and foothills assessment:
Habitat and species conservation issues. General Technical Report GTR-PSW-175. Albany, CA: Pacific
Southwest Research Station, Forest Service, U.S. Department of Agriculture.
Tactarian, G. 2001. California bat management plan – Bats in Structures. California bat working group.
Twente, J.W., Jr. 1955a. Some aspects of habitat selection and other behavior of cavern-dwelling bats.
Ecology 36: 706-732.
Twente, J.W., Jr. 1955b. Aspects of a population study on cavern-dwelling bats. Journal of Mammalogy
36: 379-390.
Western Bat Working Group. 1998. Western bat species: Regional priority matrix. Developed at
Western Bat Working Group Workshop, Reno, Nevada, February 9-13, 1998.
Zeiner, D.C.; Laudenslayer, W.F., Jr.; Mayer, K.E.; White, M., eds. 1990. California's wildlife. Volume
III: Mammals. California Statewide Wildlife Habitat Relationships System. Sacramento, CA: California
Department of Fish and Game.
Information gathered from California DFG - California Interagency Wildlife Task Group
