New York Natural Heritage Program
Indiana Bat
Myotis sodalis Miller and Allen, 1928
Mammals

Identifying Characteristics [-]
The Indiana bat is a small bat, approximately 2 inches (51 mm) in length and weighing approximately 0.2 to 0.3 ounces (6-9 grams) (Harvey et al. 1999; NYSDEC 2006). The pelage is very fine and fluffy and is dark gray to grayish-brown in color and the nose is pinkish in color (NYSDEC 2006). The feet have few hairs that do not extend beyond the tips of the toes. Indiana bats have a keeled calcar, which is a cartilaginous projection from the foot which helps support the membrane between the foot and the tail (NYSDEC 2006).

Characters Most Useful for Identification [-]
When in hand, the gray-brown pelage, pinkish nose, toe hairs that don't extend beyong the tips of the toes, and keeled calcar are used in combination to distinguish Indiana bats from little brown bats. Hibernating Indiana bats are distinguished from other bats by their tight clusters, grayish-brown pelage and pinkish noses.

Behavior [-]
Most Indiana bats migrate seasonally between traditional winter and summer roost sites. Hibernation sites include both natural caves and mines. Caves and mines chosen for hibernation have been reported to have stable temperatures below 10 degrees Celsius (50 degrees Fahrenheit) and preferably from 4-8 degrees Celsisus (39 - 46 degress Fahrenheit). Relative humidities are fairly high at hibernation sites, usually above 74 % (Hall 1962; Humphrey 1978). Depending on local weather conditions, Indiana bats hibernate from October through April (Hall 1962). Summer foraging habitat consists of wooded or semi-wooded areas and may be along streams. Indiana bats have strong fidelity to summer colony areas, roosts, and foraging habitat (USFWS 1999), and radio-telemetry studies in New York have shown this to be true for maternity roost locations. Maternity colonies are generally in hollow trees or under loose bark of living or dead trees that are often exposed to direct sunlight. Although the majority of maternity sites reported have been in riparian areas, recent studies in New York and elsewhere indicate that upland habitats are used more than previously thought (Humphrey et al. 1977; Garner and Gardner 1992).

Diet [-]
Indiana bats feed entirely on flying insects and the food items reflects the environments in which they forage. Prey items may include moths (Lepidoptera), caddisflies and flies (Diptera), mosquitos and midges, bees, wasps, and flying ants (Hymenoptera), beetles (Coleoptera), leafhoppers and treehoppers (Homoptera), stoneflies (Plecoptera), and lacewings (Neuroptera) (NatureServe 2006).
Indiana Bat Images
click to enlarge
The Best Time to See
Females begin hibernation soon after mating, whereas males often remain active through mid-October to November (Cope and Humphrey 1977). Most individuals are in hibernation by late November although some are still active until December (Barbour and Davis 1969). Activity is resumed generally in April, with few bats still in the hibernation caves by mid-May. In Michigan, bats were present at tree roosts as late as 10 September (Kurta et al. 1993). Primarily nocturnal.
J F M A M J J A S O N D
Present Active Reproducing
The time of year you would expect to find Indiana Bat present (blue shading), active (green shading) and reproducing (orange shading) in New York.
Similar Species
  • Little Brown Bat (Myotis lucifugus)
    The little brown bat differs from the Indiana bat in that it has brown pelage and its ears and nose are slightly darker than the fur (NYSDEC 2006). Little brown bat feet are are also larger and with more hairs that extend beyond the tips of the toes (NYSDEC 2006). Indiana bats have a keeled calcar, which is absent in Little brown bats.