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Eastern Red Bat (Lasiurus borealis)

Eastern Red Bat


  • The eastern red bat is a moderate size, weighing 7 to 12 grams (0.3 to 0.4 ounces).
  • Wingspan can measure up to 30 centimetres (12 inches).


  • One of the brightest-coloured bats, the eastern red bat has fur ranging from bright orange to light rusty brown.
  • Adult males are usually redder, while females are "frosted" with white.
  • Is found most commonly in the southern and eastern United States and in eastern Canada as far west as Saskatchewan.
  • Until recently, the eastern red bat was considered an infrequent visitor to Alberta. However, this species has been heard on bat detectors and captured during bat inventory projects in Alberta more frequently in recent years. The species appears far more common and widespread than was thought as little as ten years ago.
  • In eastern regions of the province, red bats have been found as far north as Ft McMurray and as far south as Drumheller. Regular observations of adult males and non-breeding females each summer in northeast Alberta suggest it may be a frequent visitor.
  • Other red bats are heard on bat detectors in late summer along the Red Deer River at the Saskatchewan border as well as near Calgary. In addition, several red bat carcasses have been found under wind turbines in southwestern Alberta near Pincher Creek.
  • It may be that this species is shifting its distribution westward, as supported by the recent detection of red bats in northeastern British Columbia.
  • The new information suggests that a reproductive population may exist in the province, but without any observations of juveniles or reproductive females, the data are not conclusive.
  • These bats are migratory and red bats collected in Alberta have been adult males and females.
Natural History


  • Eastern red bats are solitary bats that roost in the foliage of thick forest cover.
  • During the day the bats hang by one foot from the base of a leaf, giving the appearance of a dead leaf. This behaviour may provide some protection from predation by blue jays, hawks and owls. Blue jays are the primary predator on young eastern red bats.
  • Eastern red bats are well-adapted to living in an environment of fluctuating temperatures. The tail membranes are thickly furred and can be used as a blanket to cover the bat during hibernation.
  • So much heat energy is conserved through various behavioural and physiological adaptations that red bats may be unable to survive in the stable environment present in caves. This may be the reason they hibernate in trees, and under leaf litter.
Reproduction and Growth

Breeding Behaviour

  • In eastern locations, one to four young per female are born under a leaf in late May or early June.
  • No juveniles have been found in Alberta and the reproductive behaviour of this bat in western Canada is unknown.
Conservation and Management


The eastern red bat is classified as Secure in the current General Status of Alberta Wild Species report. See:


  • Mortality at current and potential wind energy projects.
  • General lack of population information.


Page Information

Updated: April 29, 2009