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BC Conservation Data Centre: Species Summary


Antrozous pallidus
Pallid Bat

 
Scientific Name: Antrozous pallidus (Le Conte, 1856)
English Name: Pallid Bat
 
Classification / Taxonomy
Scientific Name - Concept Reference: Wilson, D. E., and D. M. Reeder (editors). 1993. Mammal species of the world: a taxonomic and geographic reference. Second edition. Smithsonian Institution Press, Washington, DC. xviii + 1206 pp. Available online at: http://www.nmnh.si.edu/msw/.
Classification Level: Species
Species Group: Vertebrate Animal
Species Code: M-ANPA
Kingdom Phylum Class Order Family
Animalia Craniata Mammalia Chiroptera Vespertilionidae
   
Conservation Status / Legal Designation
Global Status: G4 (Apr 2016)
Provincial Status: S2 (Mar 2022)
BC List: Red
Provincial FRPA list:   
Provincial Wildlife Act:
COSEWIC Status: Threatened (Nov 2010)
SARA Schedule: 1  -  Threatened (Jun 2003)
General Status Canada: 1 - At Risk (2005)
   
Ecology & Life History
General Description: A large, pale bat with large ears (not joined at base), large eyes, a simple muzzle, and yellowish drab dorsal pelage (palest in deserts, darkest along coast); total length 92-135 mm; tail length 35-53 mm; hind foot length 11-16 mm; ear length 21-37 mm; forearm length 45-60 mm; skull length 18.6-24 mm; mass 13.6-24.1 g in males, 13.9-28.0 g in females (Hermanson and O'Shea 1983).
Subspecies Comments: Of the six subspecies recognized, only A. p. pallidus occurs in British Columbia (Nagorsen and Brigham 1993).
Identification Comments: The Pallid Bat is unlike any other bat in BC. It is larger than most bats, has pale fur and large ears. The snout is elongated and broad in contrast to many other species. These bats tend to be quite placid when handled. In flight, this bat can be recognized by its size, strong wing beats, and its flight pattern is low to the ground, rising and falling over obstructions in its path.
Global Reproduction Comments: Copulation usually occurs in October-December. Delayed fertilization in spring. In the U.S., young are born in late May-early June in California, mostly late June in Kansas, probably early May to mid-June in Texas (Schmidly 1991). Litter size usually is 2, sometimes 1. Young fly at 6 weeks, weaned in 6-8 weeks (Hermanson and O'Shea 1983). In Oregon, reproductive success was reduced in a year with low spring temperatures (Lewis 1993). Maternity colonies usually are small, but may include up to 200+ adults, may include adult males.
Provincial Reproduction Comments: Very little is known about reproduction in BC. The general location of four maternity roosts are derived from capturing lactating individuals, sometimes with volant juveniles (Ophiuchus Consulting 2005). Volant juveniles have also been found at several other locations but these individuals may already have dispersed from a maternity roost. It is presumed that adult females only give birth to one young but this has not been confirmed. Juvenile survivorship is also unknown.
Global Ecology Comments: This is a gregarious species. Usually it forms clusters in diurnal roosts. It may gather in night roosts that are frequently near, but separate from, day roosts (Lewis 1994). Tadarida brasiliensis and Myotis yumanensis may roost among pallid bats.

This species is a legitimate pollinator of certain agaves and cacti (Herrera et al. 1993, Frick et al. 2014).
Provincial Ecology Comments: Pallid Bats are one of the few desert-obligate bat species. This is due to their foraging technique of taking large prey items from the ground. Most adults are probably long-lived, as suggested by pronounced tooth wear of some individuals. This implies that they have a strong familiarity with their surroundings. This is supported by the use of many roost sites by adult male Pallid Bats (Rambaldini and Brigham 2003). Their inter-relationships with their environment are poorly understood.
Migration Characteristics:
(Global / Provincial)		 
    Nonmigrant:
    Local Migrant:
    Distant Migrant:
    Within Borders Migrant: 		Y / N
Y / Y
N / N
na / N
Global Migration Comments: Little information is available on seasonal movements, but individuals are believed to hibernate in the general vicinity of their summer range (Barbour and Davis 1969, Schmidly 1991, Ammerman et al. 2012).

Foraging areas generally are not far from day roosts (but up to at least 7-11 kilometers away; Brown et al. 1997, Baker et al. 2008) and sometimes much farther (Davis 1966). In the Sierra Nevada of California, lactating females had the smallest foraging areas (mean 1.56 sq km) and post-lactating females had the largest areas (mean 5.97 sq km) (Baker et al. 2008).
Provincial Mobility & Migration Comments: Very little is known of the seasonal movement patterns of Pallid Bats. Males are known to use a number of roosts throughout the active season (Rambaldini and Brigham 2003). Maternity roosts and hibernacula are unknown. Pallid Bats are thought to have separate summer and winter ranges elsewhere (O'Shea and Vaughan 1977).
Habitats:
(Type / Subtype / Dependence) 		Anthropogenic / Industrial / Facultative - occasional use
Anthropogenic / Urban/Suburban / Facultative - occasional use
Forest / Conifer Forest - Dry / Facultative - occasional use
Grassland/Shrub / Grassland / Obligate
Grassland/Shrub / Sagebrush Steppe / Facultative - frequent use
Lakes / Pond/Open Water / Facultative - occasional use
Rock/Sparsely Vegetated Rock / Cliff / Facultative - frequent use
Rock/Sparsely Vegetated Rock / Talus / Facultative - frequent use
Subterranean / Caves / Facultative - occasional use
Global Habitat Comments: Habitats include mountainous areas, intermontane basins, and lowland desert scrub (Ammerman et al. 2012); arid deserts and grasslands (Adams 2003), often near rocky outcrops and water; in some areas, this species also inhabits open coniferous forest and woodland (Baker et al. 2008). In British Columbia, pallid bats foraged over native habitats and also over vineyards (Rambaldini and Brigham 2011).

Day roosts include crevices of rock outcrops, caves, mine tunnels, buildings, bridges, and hollows of live and dead trees. Night roosts often or typically are in caves in Oklahoma (Caire et al. 1989). In Oregon, night roosts were in buildings, under rock overhangs, and under bridges; bats generally were faithful to particular night roosts both within and between years (Lewis 1994).

Hibernation occurs in caves and mines, though not very many hibernation records are available.

Young are born in maternity colonies usually in rock crevices or buildings.
Provincial Habitat Comments: This species is restricted to arid environments throughout its range. In BC, foraging is conducted in sparsely vegetated areas, most often dominated by antelope brush, big sagebrush, or ponderosa pine. Roosting typically occurs in crevices on cliffs but solitary roosting individuals can also be found in rubble. Roosting in buildings has been documented elsewhere (Tatarian 1999) but has never been observed in BC. Hibernacula have never been observed in BC (Nagorsen et al. 1993) but they are known to use crevices within a mine elsewhere (Alcorn 1944).
Food Habits: Invertivore: Adult, Immature
Nectarivore: Adult, Immature
Global Food Habits Comments: Primary diet is arthropods, often capture on the ground after an aerial search; these bats also capture some food (large insects) in flight, within a few meters of ground vegetation. Food items include flightless arthropods, moths, beetles, etc.; also may eat small vertebrates. In the southwestern United States and Mexico, pallid bats visit agaves and cactus, seeking insects (Herrera et al. 1993) or nectar (Ammerman et al. 2012, Frick et al. 2014).
Provincial Food Habits Comments: Pallid Bats primarily feed on large, ground dwelling invertebrates, such as orthopterans, beetles, and scorpions. Their preferred prey is probably the Jerusalem cricket. They are also capable of taking slow flying sphingid moths and mantids (Chapman et al. 1994). Lizards and small mammals have been documented as food items elsewhere (Chapman et al. 1994). There is also one incident of a Pallid Bat entering a Big Brown Bat (Eptisicus fuscus) maternity colony while all but one of the mothers was out feeding. The remaining mother defended the roost from what may have been an attempt to prey on the pups (M. Sarell, pers. obs.). Prey are located by noises they generate and then captured on the ground. Prey are usually consumed at night roosts to enable the bats to cull the hard parts of the prey and/or manipulate the large prey item. Feeding occurs throughout most of the night.
Global Phenology: Hibernates/aestivates: Adult, Immature
Nocturnal: Adult, Immature
Global Phenology Comments: Emerges from day roost relatively late in the day. Foraging peaks at beginning and end of nocturnal activity cycle. About 40-75% of time away from diurnal roost may be spent at night roosts. In Oregon, began entering night roosts almost immediately after the onset of emergence from the day roosts (Lewis 1994). Largely inactive in winter, believed to hibernate.
Provincial Phenology:
(1st half of month/
2nd half of month)		 June: Active / Active
July: Active / Active
Aug: Active / Active
Sept: Active /
Provincial Phenology Comments: The earliest record in the season of a Pallid Bat is 29 May (Rambaldini and Brigham 2003). The latest observation is 09 September (Ophiuchus Consulting 2005). Reproduction is poorly documented but mating appears to occur in the fall, as males do not become sexually potent until the latter part of the summer. Parturition appears to be in the latter part of June (Sarell and Haney 2000). Previous extrapolations of parturition was early July (Nagorsen and Brigham 1993). There are no winter records of Pallid Bats (Nagorsen et al. 1993).
Colonial Breeder: Y
Length(cm)/width(cm)/Weight(g): 13/ / 37
Elevation (m) (min / max): Global: 
Provincial:  340 / 700
   
 
Distribution
Endemic: N
Global Range Comment: Range includes western North America from south-central British Columbia (Okanagan Valley; small resident population; Willis and Bast 2000; Rambaldini and Brigham 2008, 2011) south through the western United States to southern Baja California, central Mexico, southern Kansas, and southern Texas; also Cuba (Martin and Schmidly 1982, Hermanson and O'Shea 1983, Reid 2006). Elevational range in Texas is 600-2,000 meters (Ammerman et al. 2012).

The following subspecies distributions are from Martin and Schmidly (1982). Subspecies pacificus: Pacific Coast Ranges of western Oregon and California south to Los Angeles and San Bernardino counties. Subspecies pallidus: east of the range of 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. Subspecies bunkeri: Barber County, Kansas, south to the western end of the Wichita Mountains in Greer County, Oklahoma. Subspecies minor: s. Baja California north through the Colorado Desert of southeastern California and southwestern Arizona, thence northward into southern Nevada. Subspecies packardi: western slopes of the Sierra Madre Occidental in southwestern Zacatecas, Jalisco, northeastern Nayarit, and southern Sonora. Subspecies koopmani: several scattered localities in Cuba.
 
Authors / Contributors
Global Information Author: Hammerson, G.
Last Updated: Apr 01, 2015
Provincial Information Author: Sarell, M.J.
Last Updated: Mar 02, 2005
   
References and Related Literature
Alcorn, J.R. 1944. Notes on the winter occurrences of bats in Nevada. J. Mammal. 25:308-310.
Arita, H. T. 1993. Conservation biology of the cave bats in Mexico. Journal of Mammalogy 74:693-702.
B.C. Ministry of Environment. Recovery Planning in BC. B.C. Minist. Environ. Victoria, BC.
Banfield, A. W. F. 1974. The mammals of Canada. University of Toronto Press, Toronto, Canada. 438 pp.
Barbour, R. W., and W. H. Davis. 1969. Bats of America. The University of Kentucky Press, Lexington, Kentucky. 286 pp.
Caire, W., J. D. Tyler, B. P. Glass, and M. A. Mares. 1989. Mammals of Oklahoma. University of Oklahoma Press, Norman. Oklahoma. 567 pp.
Chapman, K., K McGuiness, and R.M. Brigham. 1994. Status of the Pallid Bat in British Columbia. B.C. Minist. Environ., Lands and Parks, Wildl. Branch. Working Rep. WR-61. 32pp.
Engstrom, M. D., and D. E. Wilson. 1981. Systematics of ANTROZOUS DUBIAQUERCUS (Chiroptera: Vespertilionidae), with comments on the status of BAUERUS Van Gelder. Annals of Carnegie Museum 50:371-383.
Hermanson, J. W., and T. J. O'Shea 1983. Antrozous pallidus. Mammalian Species 213:1-8.
Holroyd, S.L., R.M.R. Barclay, L.M. Merk, and R.M. Brigham. 1994. A Survey of the Bat Fauna of the Dry Interior of British Columbia. B.C. Minist. Environ., Lands and Parks, Wildl. Branch. Working Rep. WR-63. 80pp.
Jones, J. K., Jr., R. S. Hoffman, D. W. Rice, C. Jones, R. J. Baker, and M. D. Engstrom. 1992a. Revised checklist of North American mammals north of Mexico, 1991. Occasional Papers, The Museum, Texas Tech University, 146:1-23.
Lewis, S. E. 1993. Effect of climatic variation on reproduction by pallid bats (ANTROZOUS PALLIDUS). Can. J. Zool. 71:1429-1433.
Lewis, S. E. 1994b. Night roosting ecology of pallid bats (Antrozous pallidus) in Oregon. Am. Midl. Nat. 132:219-226.
Manning, R. W., et al. 1988. Subspecific status of the pallid bat, ANTROZOUS PALLIDUS, in the Texas Panhandle and adjacent areas. Occas. Pap. Mus. Texas Tech Univ. 118:1-5.
Martin, C. O., and D. J. Schmidly. 1982. Taxonomic review of the pallid bat, Antrozous pallidus (Le Conte). Spec. Publ. Mus., Texas Tech. Univ. 18:1-48.
Nagorsen, D.W., et al. 1993. Winter bat records for British Columbia. Northwest. Nat. 74:61-66.
Nagorsen, D.W., and R.M. Brigham. 1993. The bats of British Columbia. Royal B.C. Mus. Handb. Victoria, BC. 164pp.
O'Shea, T.J., and T.A. Vaughan. 1977. Nocturnal and seasonal activities of the pallid bat, Antrozous pallidus. J. Mammal. 58:269-284.
Ophiuchus Consulting. 2005. Unpublished, georeferenced observations of the Pallid Bat in British Columbia. Excel 2000 database.
Ports, M. A., and P. V. Bradley. 1996. Habitat affinities of bats from northeastern Nevada. Great Basin Naturalist 56:48-53.
Rambaldini, D.A., and R.M. Brigham. 2003. Habitat Use and Roost Selection by Pallid Bats (Antrozous pallidus) in British Columbia. Prepared for the World Wildl. Fund and Can. Wildl. Serv. Endangered Species Recovery Fund. 9pp.
Ransome, R. 1990. The natural history of hibernating bats. Christopher Helm, London. xxi + 235 pp.
Sarell, M.J., and A. Haney. 2000. South Okanagan Rare Bat Inventory 2000. Prepared for B.C. Environ., Penticton. 79pp.
Schmidly, D. J. 1977. The mammals of Trans-Pecos Texas including Big Bend National Park and Guadalupe Mountains National Park. Texas A & M University Press, College Station.
Schmidly, D. J. 1991. The bats of Texas. Texas A & M University Press, College Station, Texas. 188 pp.
Stevens, V., and S. Lofts. 1988. Species Notes for Mammals. Vol. 1 in A.P. Harcombe, tech. ed. Wildlife Habitat Handbooks for the Southern Interior Ecoprovince. B.C. Minist. Environ., Lands and Parks, Wildl. Branch. Tech. Rep. R-15. 174pp.
Tatarian, G. 1999. Use of buildings and tolerance of disturbance by pallid bats Antrozous pallidus. Bat Research News 40:115.
The Pallid Bat Recovery Team. 2008. Recovery Strategy for the Pallid Bat (Antrozous pallidus pallidus) in British Columbia. Prepared for the B.C. Ministry of Environment, Victoria, B.C. 18 pp.
van Zyll de Jong, C.G. 1985. Handbook of Canadian Mammals. Vol. II, Bats. National Museum of Natural Sciences, National Museums of Canada, Ottawa, Canada. 212 pp.
Wilson, D. E., and D. M. Reeder (editors). 1993. Mammal species of the world: a taxonomic and geographic reference. Second edition. Smithsonian Institution Press, Washington, DC. xviii + 1206 pp. Available online at: http://www.nmnh.si.edu/msw/.
 

Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.

Suggested Citation:

B.C. Conservation Data Centre. 2015. Species Summary: Antrozous pallidus. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Nov 13, 2024).