Mouse-tailed bats

(Rhinopomatidae)

Class Mammalia

Order Chiroptera

Suborder Microchiroptera

Family Rhinopomatidae

Thumbnail description
The mouse-tailed bats are the only microbats with a tail nearly as long as the head and body, which extends well beyond the end of the interfemoral membrane; the large ears are connected by a band of skin across the forehead, and extend beyond the nostrils when the ears are projected forward

Size
Small to medium-sized bats with forearms ranging from 1.8 to 3 in (4.5–7.5 cm) in length and weighing 0.2–1.6 oz (6–45 g)

Number of genera, species
1 genus; 4 species

Habitat
Mouse-tailed bats are mainly found in arid habitats but also in moist, forested regions

Conservation status
Vulnerable: 1 species; Lower Risk/Least Concern: 2 species

Distribution
North Africa to Asia

Evolution and systematics

Included in the superfamily Rhinopomatoidea with the hog-nosed bats (Craseonycteridae) family, mouse-tailed bats are relatively unspecialized compared to most other groups of microchiropterans. They are not known as fossils and no subfamilies have been described.

Physical characteristics

These small to medium-sized bats have long slender tails making them among the most distinctive of microchiropterans. The valvular nostrils are without equivalent among bats, but the small flap of a noseleaf is somewhat matched by the condition in some plain-nosed bats (Vespertilionidae).

Distribution

Mouse-tailed bats occur across the Sahara from western Africa through the middle east to India, Myanmar, Thailand, and Sumatra.

Habitat

Mouse-tailed bats are mainly associated with arid habitats, although they also range into moist, forested regions. As expected from animals of arid regions, mouse-tailed bats have kidneys specialized in the production of highly concentrated urine. The urine of mouse-tailed bats is four to five times more concentrated than that of humans. These bats roost in hollows, typically in caves, abandoned mines, pyramids and wells, but also in buildings. Mouse-tailed bats emerge from their roosts around dark and forage well above (16–32 ft, or 5–10 m) the ground or vegetation. Foraging individuals can be observed over forested areas as well as over arid habitats mainly devoid of vegetation.

Behavior

Rhinopomatids often form colonies consisting of hundreds of individuals. Colonies echo with a mixture of social and echolocation calls, and individuals may or may not roost in contact with conspecifics. At some times of the year these bats lay down large fat deposits. These deposits may equal the bats' normal body mass and appear to support them through times when prey is scarce or absent (sometimes winter). Heavier individuals with body weight exceeding 1.4 oz (40 g) are those with large fat accumulations and males typically are heavier than females. In some parts of their range, some species migrate between summer and winter roosts.

Feeding ecology and diet

These aerial-feeding bats use echolocation to detect, track and assess the flying insects that they eat. The bats' echolocation

calls consist of several harmonics, with most energy in the third. Most of the sound energy is in the ultrasonic range, with species-specific variations in the actual frequencies dominating the calls. Foraging animals do not appear to be territorial, perhaps reflecting the dispersed nature of their insect prey. Their diet includes insects ranging from flying ants and termites to beetles, bugs and moths. When insect food is not easily available, or during cold seasons, they undergo periods of torpor. During winter, fat that was accumulated in the fall, is metabolized and the bat is able to survive for several weeks without water.

Reproductive biology

These bats are thought to be polygamous. Females bear a single young each year after a gestation period of about 120 days. Young are fully grown in about six weeks when they are weaned. Females attain sexual maturity in their second year. Reproduction periods differ depending on the geographic habitat of the bat and are dependent on the seasonal movement due to torpor. Young mouse-tailed bats are born in June and July in Egypt, females in Egypt and Sudan are pregnant in late March and lactate during August.

Conservation status

Two species, the greater mouse-tailed bat (Rhinopoma microphyllum) and small mouse-tailed bat (Rhinopoma muscatellum), are categorized by IUCN as Lower Risk/Least Concern. One, MacInnes's mouse-tailed bat (Rhinopoma macinnesi), is identified as Vulnerable because of the decline in available habitat for its small and restricted population.

Significance to humans

They eat many insects that humans consider pests.

Species accounts

List of Species

Hardwicke's lesser mouse-tailed bat

Rhinopoma hardwickei

taxonomy

Rhinopoma hardwickei Gray, 1831, India. Two subspecies are recognized.

other common names

None known.

physical characteristics

Smaller than some other mouse-tailed species and larger than others. Forearms ranging in length from 2.0 to 2.5 in (5.2 to 6.4 cm); weighing 0.4–0.5 oz (11–14 g).

distribution

Lesser mouse-tailed bats are found in North Africa (Morocco and Senegal to Egypt, Somalia, and Kenya), the middle east (Israel, Syria, Jordan, Lebanon, Saudi Arabia, and Yemen), Afghanistan, India, and Pakistan, as well as on Socotra Island.

habitat

A species of more arid areas, lesser mouse-tailed bats are also found in habitats ranging from deserts to dry woodland.

behavior

Lesser mouse-tailed bats roost in hollows (caves, mines, pyramids, wells, buildings) and their colonies often number in the thousands of individuals. Roosting in groups numbering from one to 10 also are common. These bats retire to sheltered roosts in extremely hot weather. During these periods they

may be relatively inactive, depending upon accumulated fat deposits for energy and water.

feeding ecology and diet

These bats eat flying insects (moths, beetles, and neuropterans) which they detect and track using echolocation. When several individuals forage together, different ones use echolocation calls dominated by different frequencies. This jamming avoidance behavior may minimize interference between bats.

reproductive biology

Female lesser mouse-tailed bats bear a single young annually after a gestation period of 90–100 days. Maximum lifespan ranges between 1 to 2 years. Thought to be polygamous.

conservation status

Rated by IUCN as Lower Risk/Least Concern.

significance to humans

Lesser mouse-tailed bats eat insects, many of which are considered pests by humans.

Resources

Books

Bates, P. J. J., and D. L. Harrison. Bats of the Indian Subcontinent. Sevenoaks, UK: Harrison Zoological Museum, 1997.

Hutson, A. M., S. P. Mickelburgh, and P. A. Racey. Global Status Survey and Conservation Action Plan, Microchiropteran Bats. Gland, Switzerland: IUCN SSC Chiroptera Specialist Group, 2001.

Kingdon, J. Mammals of East Africa: an Atlas of Evolution. Vol. 2b. New York: Academic Press, 1974.

Nowak, R. M. Walker's Mammals of the World. Vol. 1. Baltimore: Johns Hopkins University Press, 1999.

Periodicals

Schlitter, D. A., and M. B. Qumsiyeh. "Rhinopoma microphyllum." Mammalian Species 542 (1996): 1–5.

Habersetzer, J. "Adaptive Echolocation Sounds in the Bat Rhinopoma hardwickei." Journal of Comparative Physiology A144 (1981): 559–566.

Simmons, J. A., S. Kick, and B. D. Lawrence. "Echolocation and Hearing in the Mouse-tailed Bat, Rhinopoma hardwickei: Acoustic Evolution in the Echolocation of Bats." Journal of Comparative Physiology A154 (1984): 347–356.

Melville Brockett Fenton, PhD