Summary ²

The little brown bat (sometimes called little brown myotis) (Myotis lucifugus) is a species of the genus Myotis (mouse-eared bats), one of the most common bats of North America. The little brown bat has been a model organism for studying bats.

Behaviour ³

Myotis lucifugus produces frequency modulated (FM) calls at 45kHz, their fundamental frequency. These calls last 1 to 5 milliseconds and sweep from 80 to 40 kHz. Cruising bats typically produce 20 calls per second to detect prey and objects.

Myotis lucifugus alert other bats with non-echolocation calls if they are flying on a collision course during feeding. They emit this call by reducing the frequency of the terminal portion of a sweep call to 25 kHz. Additionally, they may use echolocation calls, visual cues, such as landmarks, and possibly chemical cues to locate roosts; they can find their roosts from 180 miles away. Mother and young communicate through a few, complex vocalizations. There is no information about alarm or distress calls.

Communication Channels: visual ; tactile ; acoustic ; chemical

Other Communication Modes: pheromones

Perception Channels: visual ; tactile ; acoustic ; ultrasound ; echolocation ; chemical

Conservation status ⁴

Myotis lucifugus is under no special conservation status as the species is abundant across North America. These bats thrives with expansion of human populations, as many of their roosting sites are built by humans. In spite of their overall abundance, some populations have suffered declines due to control measures and build-up of fat-soluble pesticides in their bodies.

Temperate North American bats are now threatened by a fungal disease called “white-nose syndrome.” This disease has devastated eastern North American bat populations at hibernation sites since 2007. The fungus, Geomyces destructans, grows best in cold, humid conditions that are typical of many bat hibernacula. The fungus grows on, and in some cases invades, the bodies of hibernating bats and seems to result in disturbance from hibernation, causing a debilitating loss of important metabolic resources and mass deaths. Mortality rates at some hibernation sites have been as high as 90%.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Description ⁵

"Echolocation of little brown bats has been well studied since the invention of bat detectors, electronic devices that can ""hear"" the ultrasonic calls bats make, which are usually beyond the range of human hearing. Little brown bats typically produce calls lasting about 4 milliseconds. While cruising, they emit echolocation calls about 20 times per second, spacing the pulses at 50 millisecond intervals. When attacking airborne prey, the pulse rates rise drastically, to 200 per second, with only 5 millisecond gaps between calls. The information the bats receive through echolocation allows them to orient themselves, and to locate, track, and evaluate their insect prey. Little brown bats feed near or over water, mainly on aquatic insects such as caddis flies, mayflies, and midges, and typically consume half their body weight in insects each night. Nursing females may eat up to 110 percent of their body weight each night."

Links:
Mammal Species of the World
Click here for The American Society of Mammalogists species account

Distribution ⁶

Little brown bats, Myotis lucifugus, are abundant in southern Alaska, Canada, across the United States from the Pacific to Atlantic coasts, and the higher elevation forested regions of Mexico. Although little brown bats are not found in northern Canada, individuals have been observed in Iceland and Kamchatka. Those outlying records are presumed to have been the result of accidental ship transportation by humans. Little brown bats are also absent from much of Florida, the southern Great Plains regions of the U.S., southern California, and parts of coast Virginia and the Carolinas.

Biogeographic Regions: nearctic (Native )

Food habits ⁷

Little brown bats eat insects. They are very good at catching insects, especially when they are in patches and are less than one meter away. These bats will catch whatever insects are available. Their food may be captured straight out of the air, or may be picked off of surfaces.

Little brown bats fly faster near the end of an attack when the prey is very close. They usually feed on swarms of insects. Large swarms of insect make it easier for the bats to capture them.

These bats do not protect feeding terrietories, but individuals do return to areas where they have had prior feeding success.

Females who are nursing young need more food than other bats. These females usually select larger insects than male bats or female bats without young. Little brown bats usually eat insects that are from 3 to 10 mm long. An active bat can eat half of its own body weight in insects each night. Females with nursing young eat 110 percent of their body weight per night.

These animals eat their food quickly. The food takes only 35 to 54 minutes to pass through the digestive system.

The echolocation calls used by little brown bats work the best for finding prey insects between 3 and 8 mm long. This is close to the size of insects most often eaten by these bats, which is between 3 and 10 mm. The same call is used to locate both flying and sitting insects.

Little brown bats catch insects in wooded areas, fields, and over water. These insects are captured as the bats swoop and dip through the air. Insects on the water surface may also be caught. Bats do most of their feeding about two hours after dark.

Little brown bats eat a lot of insects that live in the water. Chironomidae provide these bats with most of their food, but other aquatic insects are eaten, too. Coleoptera, Trichoptera, Lepidoptera, Ephemeroptera, Neuroptera, and Diptera are all eaten sometimes.

Animal Foods: insects

Geographic range ⁸

Little brown bats are found in most parts of North America. They are not found in the far north of Canada or in the far southern parts of the United States, except in the forested high mountains of Mexico. Some little brown bats have been observed in Iceland and Kamchatka, but those probably got there as the result of accidental ship transportation by people.

Biogeographic Regions: nearctic (Native )

Sources and Credits

1. (c) SMBishop, some rights reserved (CC BY-SA), http://commons.wikimedia.org/wiki/File:Little_Brown_Myotis.JPG
2. Adapted by rkkessler from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Myotis_lucifugus
3. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31408486
4. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31408492
5. (c) Smithsonian Institution, some rights reserved (CC BY), http://eol.org/data_objects/16146920
6. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31408481
7. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065846
8. (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065840

More Info

• iNat taxon page
• AMNH Bats of the World
• Animal Diversity Web
• ASM Mammal Diversity Database
• Biodiversity Heritage Library
• BOLD Systems BIN search
• CalPhotos
• Global Biodiversity Information Facility (GBIF)
• iNaturalist Mammal Working Group
• Maryland Biodiversity Project
• NatureServe Explorer 2.0
• VertNet
• Wikipedia

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