Silver-haired Bat
Lasionycteris noctivagans
Summary 3
The silver-haired bat (Lasionycteris noctivagans) is a species of vesper bat in the family Vespertilionidae and the only member of the genus Lasionycteris.Somewhat resembling the larger hoary bat, the silver-haired bat has frosted tips on the black or dark-brown fur of its back, this helps as a distinguishing factor between the two species. Silver-haired bats occur in both grassland and forest, and are abundant in old-growth forest. They feed on small flying insects, especially moths, using echolocation to navigate and hunt. These bats can be found in Iron County, Utah.
Conservation status 4
Silver-haired bats have no special endangered or threatened status; however, activities such as logging and deforestation may pose a threat for the bat in the future.
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%. While there are currently no reports of Lasionycteris_noctivagans mortalities as a result of white-nose syndrome, the disease continues to expand its range in North America.
IUCN Red List of Threatened Species: least concern
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Distribution 5
Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Range extends from southeastern Alaska and much of western Canada south of the Northwest Territories south to central California, northern Mexico, and east through Georgia (Yates et al. 1976, Hall 1981). The species is known also from Bermuda. In winters in the Pacific Northwest, in scattered areas of the southwestern United States, and at middle latitudes of the eastern United States approximately south of Michigan and east of the Mississippi River (Cryan 2003). Seasonal changes in the numbers of bats have been observed: more individuals are seen farther north in the summer and farther south in winter, suggesting that the species is probably migratory. Males seem to stay farther south in spring and summer than do females, except for populations in British Columbia that do not appear to migrate (Cryan 2003).
Food habits 6
Silver-haired bats are insectivorous. Their diet is mostly made up of diptera, coleoptera, and lepidoptera. However, these bats take the opportunity to feed on any concentration of insects they come across. They have a short-range feeding strategy, traveling over woodland ponds and streams. They start foraging after sunset, finding their prey at treetop level or over streams and ponds. Silver-haired bats do not always feed in mid-flight; they have been caught in mouse traps, suggesting that they look for food on the ground, and they have been reported to eat insect larvae on trees.
Animal Foods: insects
Habitat 7
Silver-haired bats prefer northern deciduous forests with ponds or streams nearby. The typical day roost for the bat is behind loose tree bark. Silver-haired bats appear to be particularly fond of willow, maple and ash trees (most likely due to the deep crevices in the bark). Hollow trees and bird nests also provide daytime roosting areas for silver-haired bats. Less common daytime roosts include buildings, such as open sheds and garages; however, due to their solitary nature and adaptation to woodland roosts, these bats rarely invade buildings in large enough numbers to cause alarm. During the winter months, silver-haired bats that hibernate find shelter in northern areas inside trees, buildings, rock crevices, and similar protected structures.
Habitat Regions: temperate
Terrestrial Biomes: forest
Physical description 8
Silver-haired bats are medium sized bats, weighing 8 to 12 grams. Measurements of these bats include: total length, 90 to 115 mm; tail length, 35 to 50 mm; wingspread, 270 to 310 mm; forearm, 37 to 44 mm; head size, 60 mm long; and a hind foot length of 6 to 12 mm. Silver-haired bats receive their name from their dark, silver-tipped fur. The fur is usually black in color, however some individuals may be dark brown with yellow-tipped fur. The ears of these bats are relatively short (15 to 17 mm in height), round, and naked. The top of the tail membrane is lightly furred, with 50 to 75% of the tail being naked.
Range mass: 8 to 12 g.
Range length: 90 to 115 mm.
Range wingspan: 270 to 310 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry Sexual Dimorphism: Females are larger than males.
Predation 9
Predators of silver-haired bats include mephitis mephitis and Bubo virginianus.
Known Predators:
- mephitis mephitis
- Bubo virginianus
- striped skunks (Mephitis_mephitis)
- great horned owls (Bubo_virginianus)
Reproduction 10
Courtship and mating of silver-haired bats occurs in autumn when both sexes gather together for migration. The embryos do not begin developing during the winter when the mother is hibernating; instead, fertilization happens the next spring. Births occur after a pregnancy of 50 to 60 days. While giving birth, the female roosts with her head facing upward. The tail membrane is bent forward to form a basket, in which the young are caught as they leave the birth canal. Two young are produced, usually between late June and early July.
Breeding season: Courtship and mating of silver-haired bats occurs in autumn.
Range number of offspring: 1 to 2.
Average number of offspring: 2.
Range gestation period: 50 to 60 days.
Average weaning age: 36 days.
Range time to independence: 21 to 36 days.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous ; sperm-storing ; delayed fertilization
Average birth mass: 1.67 g.
Average number of offspring: 2.
Average age at sexual or reproductive maturity (male)
Sex: male: 152 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 152 days.
Newborns weigh about 2g. The litter weight equals 36% of the mother's body weight. Young are born with their eyes closed, ears folded over, and most of their 22 baby teeth in place. Within a period of 21 to 36 days, young are able to find food for themselves.
Parental Investment: altricial ; pre-fertilization (Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
Scat 11
The scat of the Silver-haired bat is about 0.2-0.3 centimeters in diameter and about 0.3-1.7 centimeters in length. Bat scat is also called guano. Guano can accumulate in caves where the bats make their roosts, and it can be found in a variety of places. Scat typically has one end that is pointed and twisted.
Tracks 11
Bats do not typically land on the ground and move around on all fours, therefore there are no specific images for tracks. They tend to roost and when they are not roosting they are flying.
Sources and Credits
- (c) adamdv18, some rights reserved (CC BY-NC)
- (c) madilynnehring, all rights reserved
- Adapted by madilynnehring from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Lasionycteris_noctivagans
- (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065245
- (c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28881883
- (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065240
- (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065235
- Adapted by madilynnehring from a work by (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065236
- (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065241
- (c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/25065237
- (c) madilynnehring, some rights reserved (CC BY-SA)
