Red bats use echolocation to locate prey. They use both broadband and narrow band calls. Search phases of calls use long calls with low pulse repetition of narrow band frequencies.
Perception Channels: tactile ; acoustic ; echolocation ; chemical
Red bats are secure over most of their range and are not considered threatened.
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 Lasiurus borealis mortalities as a result of white-nose syndrome, the disease continues to expand its range in North America.
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
Unfortunately some people view red bats, along with all other bats, as vermin. However, red bats do not negatively affect humans.
Red bats rarely invade homes. Red bats keep insect populations down.
Positive Impacts: controls pest population
Red bats play an important ecosystem role as insect consumers.
Red bats are insectivorous. They capture insects while flying like many other insectivorous bats.
Red bats have been found in insect light traps. The activity of these bats around lights reflects overall flight and feeding patterns. Hunting for food begins at dusk and the bat proceeds to hunt within 500 m of a light source (Hickey et al 1996). Foraging activies of this bat are generally concentrated into one feeding bout, but there are records of these bats foraging throughout the night. Their food consists of different kinds of insects: moths, beetles, plant-hoppers, ants, flies, and others.
Red bats make one pass through a concentration of potential prey, fixing on a target within 5 to 10 m. They attack insects, on average, every thirty seconds and are successful fourty percent of the time. If a bat is stalking a moth using echolocation the moth can hear this and will try to flee the attack by diving. The bat will follow the moth into a steep dive and often will pull away within inches of the ground. Humans observing this predator-prey interaction only see the bat and not the fleeing moth and may believe that the bat is acting aggressively towards them.
There is a distinct body and head posturing change in this bat when in pursuit of prey. It has been said that if you observe a rural street light and see a bat dipping and diving, that you are most likely viewing a red bat.
Animal Foods: insects
Primary Diet: carnivore (Insectivore )
Lasiurus borealis, or red bats, are widely distributed in forested regions, occurring from southern Canada through Central America and into Chile and Argentina. Red bats migrate to warmer regions during winter.
Biogeographic Regions: nearctic (Native ); neotropical (Native )
Lasiurus borealis are fast flying bats that live throughout the Americas. They tend to choose habitats that are sparsely to moderately populated by humans and are rare in heavily urbanized areas.
Habitat Regions: temperate ; tropical
Terrestrial Biomes: forest
Red bats are medium sized bats having a total length of 93 to 117 mm. Body length is approximately 40 to 50 mm and weight ranges between 7 to 13 g. The hindfoot length is 6 to 11 mm. Height of the ear from the notch is 8 to 13 mm. Length of the forearm varies between 36 and 46 mm.
Pelage varies in color from a brick red to a yellowish red. The fur is white at the tips giving these bats a frosted appearance. In general, female bats appear more frosted compared to males, and males have a redder color than females. There is no documented sexual dimorphism in size. The uropatagium is thickly furred on the dorsal side and helps to keep these bats warm in cold weather.
Lasiurus borealis have small and heavily constructed skulls. The arrangement of the 32 teeth is distinctive and shared with other Lasiurus species. Red bats have a tiny cone shaped upper premolar that is located at the inner junction of the upper canine and the second premolar.
Red bats have been called by Allen Kurta, author of "Mammals of the Great Lakes," one of the "most handsome mammals in the Great Lakes region."
Range mass: 7 to 13 g.
Range length: 93 to 117 mm.
Sexual Dimorphism: sexes colored or patterned differently
Other Physical Features: endothermic ; bilateral symmetry
Predators of red bats include birds of prey and opossums. Humans and human constructions have also taken their toll on red bats. "There have been documented cases of these bats being impaled by barbed wire, . . . entrapped on road surface oil . . ., flying into lighthouses . . ., and radiator grills of automobiles . . ." (Baker, 1983, pg. 123).
Red bats avoid predators through the use of camouflage.
Known Predators:
Anti-predator Adaptations: cryptic
An incomplete account of a red bat mating in flight was made in 1947. A bat biologist was fly fishing and watched as he saw what looked like a single bat tumble onto the bank. The biologist inspected with his flashlight, and saw what he originally thought was a female bat with young clinging to her. Under closer inspection the biologist saw that a male had clasped itself to the back of the female therefore making it impossible for either to fly. It seemed as if the male red bat had attached itself to the female in mid-flight. The male bat seemed to hold his position by hooking his claw over the female's wing.
Mating takes place in flight and copulation usually occurs in August or September. The sperm is stored until the spring, usually March or April. Female red bats possess four mammary glands while most other chiropterans have two. Female red bats give birth to one litter of twins each year, unlike most bats which give birth to single young. Newborn bats are hairless and weigh approximately 1.5 g. The young learn to fly at about five weeks old.
Breeding interval: Red bats breed once each year.
Breeding season: Mating occurs in August or September.
Range number of offspring: 1 to 4.
Average number of offspring: 2.
Range gestation period: 80 to 90 days.
Average weaning age: 38 days.
Average time to independence: 5 weeks.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous ; sperm-storing ; delayed fertilization
Like all mammals, female red bats nurse their young until the young are able to fend for themselves. It takes young red bats about five weeks to learn how to fly and forage on their own.
Parental Investment: pre-fertilization (Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)
