Old World Leaf-Nosed Bats (Hipposideridae)

(Hipposideridae)

Class: Mammalia

Order: Chiroptera

Suborder: Microchiroptera

Family: Hipposideridae

Thumbnail description
This large family is characterized by elaborate modifications of the nose and muzzle, forming leaf-like projections that are thought to help focus echolocation signals emitted through the nose

Size
Range in size from small to very large, with head and body lengths of 1.1–4.3 in (28–110 mm), and forearms a similar length

Number of genera, species
9 genera; 66 species

Habitat
Occupy a variety of habitats, from arid to tropical areas throughout much of the Old World

Conservation status
Critically Endangered: 2 species; Endangered: 1 species; Vulnerable: 15 species; Lower Risk/Near Threatened: 23 species; Data Deficient: 7 species

Distribution
Old World tropics and subtropics

Evolution and systematics

Similar in diversity, size, and characteristics to horseshoe bats (family Rhinolophidae), Old World leaf-nosed bats are sometimes considered a subfamily (Hipposiderinae, but sometimes referred to as the subfamily Rhinonycterinae) of Rhinolophidae. Recent analyses of large molecular and morphological datasets place Hipposideridae in a large group along with the bat families Craseonycteridae, Rhinopomatidae, Nycteridae, Megadermatidae, and Rhinolophidae, all of which are exclusively Old World in distribution.

A recent study employing primarily nuclear sequence data suggests that the group, including Hipposideridae (with the exception of Nycteridae), is more closely related to flying foxes (Megachiroptera) than to other microbats (Microchiroptera). This study also provides some morphological support for their assertions. If this finding is supported by additional evidence and analyses, it would mean that either the general characteristics associated with microbats (echolocation and various morphological features) have evolved twice independently or that they have been lost in the megachiropteran lineage.

A systematic analysis, based on morphological features, of relationships among bats in the family Hipposideridae suggested that the genus Hipposideros is actually composed of three distinct groups, which may deserve generic status. In general, relationships among hipposiderid bats are poorly understood and additional research is needed to fully understand the pattern of evolutionary history in this group. These bats are known from the Eocene to Oligocene in the fossil record.

Physical characteristics

Bats in this family vary greatly in size, from small to very large. Head and body lengths are 1.1–4.3 in (2.8–11 cm) and forearms are a similar length. One of the largest insectivorous bat species is a hipposiderid, Commerson's leaf-nosed bat (Hipposideros commersoni). They are characterized by their elaborate, leaf-like nose leaves, which are composed of an anterior, horseshoe-shaped portion and a posterior portion that is often lobed. Lateral leaflets are also present in many species. These elaborate facial appendages seem to be related to their use of nasal echolocation, where nose leaves act to focus and modify emitted echolocation signals. The ears of these bats vary in size but always lack a tragus, the anterior ear appendage found in many microbats. Members of the families Hipposideridae and Rhinolophidae share a unique feature of the premaxillary bones, whereby premaxillae on either side of the skull are not fused to each other or to the maxillae. Fur coloration is generally shades of brown and red. Tail length ranges from zero (nonexistant) to 2.4 in (6 cm).

Their teeth are much like those of other insectivorous bats, the dental formula is I1/2 C1/1 P1–2/2–3 M3/3.

Distribution

Hipposiderids are found mainly in tropical and subtropical regions of the Old World, including Africa, Asia, and Australia.

Habitat

These bats are found in a variety of habitats, from deserts to tropical rainforests. Most are found in moist, lowland areas.

Behavior

The majority of species in the family Hipposideridae are only poorly known. They are a diverse group and exhibit a variety of life history strategies, social structures, and behaviors. Some northern populations of this family hibernate, such as some of the genus Hipposideros, while others are active year-round, and only one species is thought to migrate. Most roost in groups varying in size from small (as few as 12) to very large (5,000) congregations, though some are solitary. Roosting often occurs in caves and tunnels, but some species also roost in hollow trees, human structures, and the burrows of animals. The fulvus roundleaf bat (Hipposideros fulvus) roosts in African porcupine (Hystrix) burrows.

Many hipposiderid species have a small sac that sits behind the nose leaf. The sac secretes a waxy substance and is mainly found in males, suggesting the possibility that it is used in social or reproductive interactions for attracting mates or for male competiton.

Feeding ecology and diet

Hipposiderids are generally insectivorous. Little information is available on the specific diets of most species, although most seem to capture insects in flight. Many species return to a roost to eat captured prey.

These bats seem to fly with their mouths closed, emitting ultrasonic pulses through the nose. The many and various modifications of the nose leaf are presumably adaptations to specific modes and frequencies of nasal echolocation. Indeed, some evidence supports a proportional relationship between call frequency and nose leaf width in several species of hipposiderids. This relationship was independent of both body size and generic affiliation. Where studied, echolocation calls tend to be constant frequency and frequency modulated, with frequencies potentially varying with sex and age of individuals.

Reproductive biology

In general, very little is known about reproduction in these bats, but they may be polygynous. Females typically give birth to a single young each year, with breeding occurring seasonally. Hipposiderids mate during the fall and females store the sperm internally during the winter, becoming fertilized and giving birth the following year. Age of weaning, age at first flight, and age at sexual maturity may be correlated with latitude, with tropical species taking longer than temperate species to achieve all of the above landmarks. In Hipposideros, eight tropical species reached sexual maturity at 16–24 months, one subtropical species at less than 12 months, and two temperate species at 6–8 months. The subtropical species (H. terasensis) is weaned at seven weeks old, while tropical species are weaned at 8–20 weeks old.

Conservation status

The majority of bats in this large family are poorly studied, so potential conservation concerns are unknown. Some species are common, others are rare and restricted to islands, making them especially vulnerable to threats such as habitat and roost destruction. The IUCN lists two species as Critically Endangered, one as Endangered, 15 as Vulnerable, 23 as Lower Risk/Near Threatened, and 7 as Data Deficient.

Significance to humans

These primarily insectivorous bats help to control insect pest populations throughout their ranges. Their dung may also be used locally as a fertilizer.

Species accounts

Resources

Bogdanowicz, Wieslaw, and Robert D. Owen. "In the Minotaur's Labryinth: Phylogeny of the Bat Family Hipposideridae." In Bat Biology and Conservation, edited by Thomas H. Kunz and Paul A. Racey. Washington, DC: Smithsonian Institution Press, 1998.

Hill, John E., and James D. Smith. Bats, A Natural History. London: British Museum of Natural History, 1984.

Koopman, Karl F. "Chiroptera: Systematics." In Handbook of Zoology. Volume VIII, Mammalia, edited by J. Niethammer, H. Schliemann, and D. Starck. Berlin: Walter de Gruyter, 1994.

McKenna, Malcolm C., and Susan K. Bell, eds. Classification of Mammals Above the Species Level. New York: Columbia University Press, 1997.

Nowak, Ronald M. Walker's Bats of the World. Baltimore: Johns Hopkins University Press, 1994.

Simmons, Nancy B., and Jonathan H. Geisler. "Phylogenetic Relationships of Icaronycteris, Archaeonycteris, Hassianycteris, and Palaeochiropteryx to Extant Bat Lineages, with Comments on the Evolution of Echolocation and Foraging Strategies in Microchiroptera." Bulletin of the American Museum of Natural History, Number 235. New York: American Museum of Natural History, 1998.

Brosset, A. "Recherches sur la Biologie des Chiropteres Troglophiles dans le Nord-est du Gabon." Biologie du Gabon 5 (1969): 93–116.

Cheng, H. C., and L. L. Lee. "Postnatal Growth, Age Estimation, and Sexual Maturity in the Formosan Leaf-nosed Bat (Hipposideros terasensis)." Journal of Mammalogy 83 (2002): 785–793.

Churchill, S. H. "Reproductive Ecology of the Orange Horseshoe Bat, Rhinonycteris aurantius (Chiroptera: Hipposideridae), a Tropical Cave-dweller." Wildlife Research 22 (1995): 687–698.

Habersetzer, J., and G. Marimuthu. "Ontogeny of Sounds in the Echolocating Bat Hipposideros speoris." Journal of Comparative Physiology, A. Sensory, Neural, and Behavioral Physiology 158 (1986): 247–257.

Hill, J. E. "A Revision of the Genus Hipposideros." Bulletin of the British Museum of Natural History, Zoology 11 (1963): 1–129.

Jones, G., M. Morton, P. M. Hughes, and R. M. Budden. "Echolocation, Flight Morphology, and Foraging Strategies of Some West African Hipposiderid Species." Journal of the Zoological Society of London 230 (1993): 385–400.

Robinson, Mark F. "A Relationship between Echolocation Calls and Nose-leaf Widths in Bats of the Genera Rhinolophus and Hipposideros." Journal of the Zoological Society of London 239 (1996): 389–393.

Teeling, Emma C., Ole Madsen, Ronald A. Van Den Bussche, Wilfried W. de Jong, and Michael J. Stanhope. "Microbat Paraphyly and the Convergent Evolution of a Key Innovation in Old World Rhinolophoid Microbats." Proceedings of the National Academy of Sciences 99 (2002): 1431–1436.

Gulf of Guinea Conservation Group. CP289, Sao Tome, Sao Tome e Principe. Phone: (230) 225428. E-mail: info@ggcg.st Web site:

[Article by: Tanya Dewey]