Big Brown Bat

Eptesicus fuscus

General Status Rank: 
Undetermined
ELCODE: 
AMACC04010
Common Name: 
Big Brown Bat
Scientific Name: 
Eptesicus fuscus
Naming References: 
B149
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Taxonomy
Group: 
Mammal (Terrestrial Mammal)
Kingdom: 
Animalia
Phylum: 
Chordata
Class: 
Mammalia
Order: 
Chiroptera
Family: 
Vespertilionidae
Habitat
Roost in tree cavities/bark, rock crevices, and buildings. Females tend to form small colonies (R160). There is evidence of big brown bats hibernating at South Slave Hibernaculum in the NWT (ENR unpublished data, 2013; Wilson et al., 2014); this species is known to hibernate in Wood Buffalo National Park, Alberta (Reimer et al., 2014).
References: 
R160
A398
A401
Distribution

Ecozones

Taiga Cordillera, Taiga Plains
References: 
R160

Distribution

163,307 km2 (SARC, 2017). Nahanni to Wood Buffalo National Park (Taiga Plains Mid-boreal and Taiga Cordillera Mid-boreal).
Score: 
F
References: 
R160

Number of Occurrences

2 individuals captured in mist net at 2 locations: Flood Plain downriver of Flood Creek on River Left and Raven Lake near First Polje 1 (Nahanni study) (R160). There are confirmed records (captures) of big brown bats from the South Slave region, from Wood Buffalo National Park, Fort Smith area, and South Slave Hibernaculum. There are also unconfirmed acoustic records from the Fort Smith area (Lausen, 2011; Wilson et al., 2014). Together, they suggest big brown bats are common in this area of NWT (Wilson et al., 2014). Evidence of guano in a cave in the Sahtu was submitted for DNA testing, and is confirmed to be from this species (Sahtu Region Bat, Cave and Karst Field Investigation, 2018). However, this cave is probably not a hibernaculum. Quantity of guano was minimal; the bat was probably just roosting there for a short time.
Score: 
AB
References: 
R160
A398
A401

Area of Occupancy

71,576 km2 (SARC, 2017)
Score: 
H
Threats

Threats

White-nose syndrome (WNS) is a fungal disease associated with mass die-offs of hibernating bats. WNS has killed more than 5.5 million bats in the northeastern United States and eastern Canada. It continues to spread rapidly but has not yet reached western or northern Canada (www.whitenosesyndrome.org). WNS has been confirmed to cause infection and significant mortality in big brown bats but big brown bats tend to experience lower mortality rates compared to Myotis species (Langwig et al., 2012; Frick et al., 2015; Frank et al., 2014; Turner et al., 2011 in H317).
Score: 
AC =
References: 
H317

Intrinsic Vulnerability

Score: 
-
References: 
H317
General Status Rank
Rank: 
Undetermined
Status Rank Description: 
We know this species is susceptible to white-nose syndrome (WCS) when hibernating, and we have evidence that this species hibernates in the NWT. Threat of WNS to this species is significant, although observed mortality due to WNS is less than for Myotis species (e.g. ~40% mortality recorded instead of ~90%; Turner et al., 2011).
S Rank: 
SU
Decision Process Description: 
New rank after publication of NWT species 2006-2010. Reviewed in 2010, modified to may be at risk (J. Wilson), retained undetermined (S. Carriere). Reviewed in 2015, modified to may be at risk due to more information. Reviewed in 2020, modified from may be at risk to undetermined after formal assessment of Data Deficient (SARC, 2017).
Last Updated: 
February 15, 2024
Status Designations

NWT - Assessment by Species at Risk Committee

NWT SARC Assessment: 
Data Deficient
2017

References

Ecozones

  • Lausen, Cori (2006) Bat survey of Nahanni National Park Reserve and surrounding areas, Northwest Territories.. Unpublished report prepared for Paks Canada and Candian Parks ad Wilderness Society, NWT Chapter Mammal binder - R160 Return

Habitat

  • Lausen, Cori (2006) Bat survey of Nahanni National Park Reserve and surrounding areas, Northwest Territories.. Unpublished report prepared for Paks Canada and Candian Parks ad Wilderness Society, NWT Chapter Mammal binder - R160 Return
  • Wilson, JM, Reimer, JP, Allaire, D. and Lausen, CL (2014) Northwestern Naturalist 95:197-218 - A398 Return
  • LAUSEN CL, WAITHAKA J, TATE D. (2014) Northwestern Naturalist 95:186–196. - A401 Return

Intrinsic Vulnerability

  • Wilson J. (2015) e-mail sent to S Carriere 21/04/2015 e-copy - H317 Return

Naming

  • Baker, R. J., L. C. Bradley, R. D. Bradley, J. W. Dragoo, M. D. Engstrom, R. S. Hoffman, C. A. Jones, F. Reid, D. W. Rice, and C. Jones. (2003) Revised checklist of North American mammals north of Mexico, 2003.. Museum of Texas Tech University Occasional Papers 229:1-23. - B149 Return

Number of Occurrences

  • Lausen, Cori (2006) Bat survey of Nahanni National Park Reserve and surrounding areas, Northwest Territories.. Unpublished report prepared for Paks Canada and Candian Parks ad Wilderness Society, NWT Chapter Mammal binder - R160 Return
  • Wilson, JM, Reimer, JP, Allaire, D. and Lausen, CL (2014) Northwestern Naturalist 95:197-218 - A398 Return
  • LAUSEN CL, WAITHAKA J, TATE D. (2014) Northwestern Naturalist 95:186–196. - A401 Return

Range Extent

  • Lausen, Cori (2006) Bat survey of Nahanni National Park Reserve and surrounding areas, Northwest Territories.. Unpublished report prepared for Paks Canada and Candian Parks ad Wilderness Society, NWT Chapter Mammal binder - R160 Return

Threats

  • Wilson J. (2015) e-mail sent to S Carriere 21/04/2015 e-copy - H317 Return