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BC Conservation Data Centre: Species Summary


Euderma maculatum
Spotted Bat

 
Scientific Name: Euderma maculatum (J.A. Allen, 1891)
English Name: Spotted 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-EUMA
Kingdom Phylum Class Order Family
Animalia Craniata Mammalia Chiroptera Vespertilionidae
   
Conservation Status / Legal Designation
Global Status: G4 (Apr 2016)
Provincial Status: S3S4 (Mar 2022)
BC List: Blue
Provincial FRPA list: Y (May 2004)  
Provincial Wildlife Act:
COSEWIC Status: Special Concern (Nov 2014)
SARA Schedule: 1  -  Special Concern (Jul 2005)
General Status Canada: 3 - Sensitive (2005)
   
Ecology & Life History
General Description: Huge pink ears (37-47 mm [Hall 1981] or 45-50 mm [Watkins 1977]); blackish dorsum with a large white spot on each shoulder and on the rump, and white patches at the posterior base of each ear; total length 107-115 mm; forearm 48-51 mm; 16-20 g; greatest length of skull 18.4-19.0 mm (small sample); supraorbital region of skull sharply ridged; no median sagittal crest; 34 teeth (Watkins 1977, Handley 1959, Hall 1981). The newborn young lack any indication of having the adult color pattern (van Zyll de Jong 1985). Four hours after birth, a male weighed 4 g and measured 59 mm in length; tail length was 20 mm, hind foot 11 mm, ear 12 mm, and forearm 21 mm.
Global Reproduction Comments: Copulation likely occurs in late summer or fall. Births apparently occur in late May or early June in the south (Snow 1974, Watkins 1977, Schmidly 1977), mid-June to early July in the north (Watkins 1977, Nagorsen and Brigham 1993). Litter size is one. Lactating females have been netted on June 23, 30, and July 1 in New Mexico, on July 9 in New Mexico by Mike Bogan, and on August 10, 15, and 18 in Utah (Barbour and Davis 1969). Females are not known to form maternity colonies (Hayes and Wiles 2013).
Global Ecology Comments: Apparently relatively solitary but may hibernate in small clusters (Whitaker 1980). In British Columbia, individuals roosted solitarily during the active season; appeared to maintain exclusive foraging areas (Leonard and Fenton 1983).

Apparently this bat is a rapid flyer. Many of them are injured in the mist nets, indicating a high rate of speed at the collision (Snow 1974). In flight, the ears project forward. The only times the ears are carried erect are when the bat is alert, usually just preparatory to flight. At all other times, the ears lie along the back and are slightly curved (Barbour and Davis 1969).

Vocalizations and Echolocation

The spotted bat makes a wide variety of sounds in communicating and foraging. The voice has been described as sounding like a soft, extremely high-pitched metallic squeak; a hissing noise and a ratlike squeak; and a typical bat chirp. This bat has also been heard clicking the teeth together and making grinding noises by gnashing the teeth. Previous to taking flight, the spotted bat makes clicking or ticking notes (Snow 1974).

The echolocation call is loud and high- pitched; the fundamental frequency sweeps from 12 to 6 kHz and is a double or single steep frequency modulated pulse. The call is repeated at a rate of two to six per second. The sound pressure level is estimated at 80-90 dB at 10 cm, making it a moderate intensity. The echolocation call can clearly be heard by a human at distances of 250 m (van Zyll de Jong 1985).

The low frequency of the echolocation call is useful in both hunting and communications. Due to reduced attenuation and good propagation qualities, the call is good for long-range detection of prey and an increased range of audibility by other bats. The bat is also able to approach the moth more closely and enhance the chance of a successful pursuit due to the moth not being able to detect the low intensity of sound (van Zyll de Jong 1985). Similar calls are made by Plecotis phyllotis (Allen's big-eared bat), Tadarida macrotis (big freetail bat), and Eumops perotis (western mastiff bat) (Snow 1974).
Migration Characteristics:
(Global / Provincial)		 
    Nonmigrant:
    Local Migrant:
    Distant Migrant:
    Within Borders Migrant: 		Y /
Y /
N /
na /
Global Migration Comments: Seasonal changes in distribution are poorly known. In some areas, the bats may occupy higher elevation coniferous stands in summer and migrate to lower elevations in late summer/early fall (Berna 1990, Barbour and Davis 1969, Geluso 2000).

In northern Arizona, radio-tagged individuals had home ranges that averaged 297 sq km (95 percent use, minimum convex polygon) (Chambers et al. 2011). Individuals used a mean of 1.4 roosts during 10 days.

In northern Arizona, a radio-tagged lactating female traveled 38.5 km from her day roost to forage over a higher elevation (~2,500 meters) meadow system (Rabe et al. 1998).

In British Columbia, individuals foraged up to 6-10 km from the day roost (Wai-Ping and Fenton 1989).
Habitats:
(Type / Subtype / Dependence) 		Agriculture / Pasture/Old Field / Facultative - occasional use
Forest / Conifer Forest - Dry / Facultative - frequent use
Grassland/Shrub / Sagebrush Steppe / Facultative - frequent use
Riparian / Riparian Shrub / Facultative - occasional use
Rock/Sparsely Vegetated Rock / Cliff / Facultative - frequent use
Rock/Sparsely Vegetated Rock / Rock/Sparsely Vegetated Rock / Facultative - frequent use
Rock/Sparsely Vegetated Rock / Talus / Facultative - frequent use
Wetland / Marsh / Facultative - frequent use
Global Habitat Comments: This species occurs in various habitats from desert to montane coniferous stands, including open ponderosa pine, pinyon-juniper woodland, canyon bottoms, riparian and river corridors, meadows, open pasture, and hayfields. Active foraging may be mostly in open terrain, including forest clearings, meadows, and open wetlands, sometimes in open areas near buildings (see review in Schmidt 2003) or even golf courses. Roosts, including maternity roosts, generally are in cracks and crevices in cliffs (Wai-Ping and Fenton 1989, Pierson and Rainey 1998, Rabe et al. 1998), sometimes in caves or in buildings near cliffs (Sherwin and Gannon 2005). Winter habits poorly known.

In British Columbia, individuals used the same roost each night May-July, but not after early August (Wai-Ping and Fenton 1989). They foraged mainly in fields near pines and over marshes (Wai-Ping and Fenton 1989).

In Wyoming, these bats were associated with canyons, cliffs, and nearby permanent water, in areas including xeric-shrub grassland, riparian woodland, and high-elevation conifer and aspens habitats (Priday and Luce 1999).

In northwestern Colorado, spotted bats are locally common in various habitats (pinyon-juniper woodland, riparian corridors, over river) in canyons (Navo et al. 1992).

In Garfield County, Utah, Easterla captured a spotted bat in an area that was treeless and rolling for several miles around the site and also surrounded by mountainous terrain. The predominant plant species were sagebrush and rabbitbrush. In the mountainous terrain, the predominant plant was ponderosa (yellow) pine (Snow 1974). In Utah, Snow (1974) reported that bats were captured over a waterhole near limestone cliffs with cracks.

In northern Arizona, radio-tagged individuals foraged mostly in desert scrub but also used woodlands and forests. Maternity roosts were remote and difficult to access (Chambers et al. 2011).

Many bats in New Mexico were caught over waterholes near a sandstone cliff with numerous vertical cracks.

In the Big Bend National Park in Texas, spotted bats were captured near the only water source (a permanent pool) in many square miles, in a shallow, barren, hot, dry canyon with walls of angled, buckled pink and red limestone. The predominant plant species were creosote bush, candelilla, Hechtia, agave, pricklypear, and ocotillo (Snow 1974).
Food Habits: Invertivore: Adult, Immature
Global Food Habits Comments: The diet is dominated by moths (Noctuidae, Lasiocampidae, Geometridae) and includes a small percentage of other insects (Berna 1990, Snow 1974; Schmidly 1977, 1991; Barbour and Davis 1969; van Zyll de Jong 1985, Painter et al. 2009).

In British Columbia, spotted bats flew 5-15 meters above the ground when foraging; foraging areas of different individuals overlapped (Wai-Ping and Fenton 1989). In southeastern Utah, the bats fed on small insects within 2 meters of the ground; sometimes they captured insects on the ground (Poche and Bailie 1974), though this has been disputed. In Colorado, spotted bats foraged at heights above 10 meters (Navo et al. 1992).

One study stated that the bats hunted a regular beat and searched for prey in clearings in pine forest; the bat was extremely punctual in making its rounds and reached various points along its route at the same time every night. When in the clearings, the bat followed a definite circuit at or above treetop height. The bat spent approximately three to five minutes per clearing during the spring, and much longer during the summer, retracing its circuit in the clearing. The lengthier foraging in the summer is attributed to increased prey availability during the later season (van Zyll de Jong 1985). Another study found that a predictable pattern of foraging was observed in spring to midsummer (May to July), and a less predictable pattern later in the summer. At the beginning of the summer, foraging periods were long, and they became shorter later in summer (van Zyll de Jong 1985). The contradiction in foraging strategies between the two studies was attributed to the variability of the bat's behavior in response to changes in one or more factors in the environment such a abundance and distribution of prey (Snow 1974).
Global Phenology: Hibernates/aestivates: Adult, Immature
Nocturnal: Adult, Immature
Global Phenology Comments: Activity may occur year-round in the warmer portions of the range but is not known to occur in the cold season in the northern range. Foraging occurs throughout the night, from after sunset to early morning (Wai-Ping and Fenton 1989, Berna 1990, Navo et al. 1992, Storz 1995, Perry et al. 1997, Rabe et al. 1998, Priday and Luce 1999).

Nearly all of 54 individuals netted in western Texas were caught after midnight (Watkins 1977). In British Columbia, the bats left their day roost an average of 49 minutes after sunset (13 minutes in radio-tagged bats, Wai-Ping and Fenton 1989), returned an average of 67 minutes before sunrise; a peak in foraging occurred at 0000-0300 hours (Leonard and Fenton 1983); emergence from day roosts was not significantly influenced by moonlight; flew continuously between departure from and return to day roost (Wai-Ping and Fenton 1989). In Colorado, spotted bats were active throughout the night (Navo et al. 1992, Storz 1995).
Provincial Phenology:
(1st half of month/
2nd half of month)
Colonial Breeder: N
Length(cm)/width(cm)/Weight(g): 13/ / 18
Elevation (m) (min / max): Global: 
Provincial: 
   
 
Distribution
Endemic: N
Global Range Comment: Range encompasses western North America from southern British Columbia (north to Fraser River basin near Williams Lake) (Cannings et al. 1999) and south-central Montana south through central and eastern Washington, eastern Oregon, Idaho, western Wyoming, western Colorado, western and southern Nevada, California (Pierson and Rainey 1998), Arizona, western and central New Mexico, and western Texas to central Mexico (Queretaro) (Verts and Carraway 1998, Luce and Keinath 2007). Distribution appears to be patchy with availability of suitable habitat (suitable roosting cliffs and water sources). Winter range is poorly known. Elevational range extends from below sea level to 3,230 meters (Luce and Keinath 2007).
 
Authors / Contributors
Global Information Author: Hammerson, G.
Last Updated: Apr 27, 2015
Provincial Information Author:
Last Updated:
   
References and Related Literature
B.C. Ministry of Environment. Recovery Planning in BC. B.C. Minist. Environ. Victoria, BC.
Barbour, R. W., and W. H. Davis. 1969. Bats of America. The University of Kentucky Press, Lexington, Kentucky. 286 pp.
Berna, H. J. 1990. Seven bat species from the Kaibab Plateau, Arizona, with a new record of Euderma maculatum. Southwest. Nat. 35:354-356.
Blood, D.A. 1993. Spotted Bat. B.C. Minist. Environ., Lands and Parks, Wildl. Branch. 6 pp.
British Columbia Ministry of Water, Land and Air Protection. 2004. Spotted Bat in Accounts and measures for managing identified wildlife. British Columbia Ministry of Water, Land and Air Protection, Victoria, BC. 52pp.
COSEWIC. 2004e. COSEWIC assessment and update status report on the spotted bat Euderma maculatum in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 26 pp.
Fenton, M. B., D. C. Tennant, and J. Wyszeck. 1987. Using echolocation calls to measure distribution of bats: the case of Euderma maculatum. Journal of Mammalogy 68:142-144.
Fenton, M.B., D.C. Tennant, and J. Wyszecki. No date. Survey Report.
Frost, D. R., and R. M. Timm. 1992. Phylogeny of plecotine bats (Chiroptera: "Vespertilionidae"): proposal of a logically consistent taxonomy. Am. Mus. Novitates 3034:1-16.
Garcia, P.F.J., S.A. Rasheed, and S.L. Hoylroyd. 1995. Status of the Spotted Bat in British Columbia. B.C. Minist. Environ., Lands and Parks, Wildl. Branch. Working Rep. WR-75. 32pp.
Hall, E. R. 1981a. The Mammals of North America, second edition. Vols. I & II. John Wiley & Sons, New York, New York. 1181 pp.
Handley, C. O., Jr. 1959. A revision of American bats of the genera Euderma and Plecotus. Proceedings U.S. National Museum 110:95-246.
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.
Hoofer, S. R., and R. A. Van Den Bussche. 2001. Phylogenetic relationships of plecotine bats and allies based on mitochondrial ribosomal sequences. Journal of Mammalogy 82:131-137.
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.
Leonard, M. L., and M. B. Fenton. 1983. Habitat use by spotted bats (Euderma maculatum, Chiroptera: Vespertilionidae): roosting and foraging behavior. Can. J. Zool. 61:1487-1491.
Navo, K. W., J. A. Gore, and G. T. Skiba. 1992. Observations on the spotted bat, Euderma maculatum, in northwestern Colorado. Journal of Mammalogy 73:547-551.
Poche, R. M., and G. L. Bailie. 1974. Notes on the spotted bat (Euderma maculatum) from southwest Utah. Great Basin Naturalist 34:254-256.
Priday, J., and B. Luce. 1999. New distributional records for spotted bat (Euderma maculatum) in Wyoming. Great Basin Naturalist 59:97-101.
Qumsiyeh, M. B., and J. W. Bickham. 1993. Chromosomes and relationships of long-eared bats of the genera Plecotus and Otonycteris. Journal of Mammalogy 74:376-382.
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.
Spahr, R., L. Armstrong, D. Atwood, and M. Rath. 1991. Threatened, endangered, and sensitive species of the Intermountain Region. U.S. Forest Service, Ogden, Utah.
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.
Storz, J. F. 1995. Local distribution and foraging behavior of the spotted bat (Euderma maculatum) in northwestern Colorado and adjacent Utah. Great Basin Naturalist 55:78-83.
Tumlison, R., and M. E. Douglas. 1992. Parsimony analysis and the phylogeny of the plecotine bats (Chiroptera: Vespertilionidae). Journal of Mammalogy 73(2):276-285.
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.
Wai-Ping, V. and M. B. Fenton. 1989. Ecology of spotted bat (Euderma maculatum) roosting and foraging. Journal of Mammalogy 70:617-622.
Watkins, L.C. 1977. Euderma maculatum. Mammalian Species, 77:1-4.
WESTEC Service, Inc. 1981. 810400. Status Report submitted to the Office of Endangered Species.
Whitaker, J. O., Jr. 1980. The Audubon Society field guide to North American mammals. Alfred A. Knopf, New York. 745 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: Euderma maculatum. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Apr 25, 2024).