Rhinolophidae

Diversity

Rhinolophidae includes approximately 77 species in a single genus, Rhinolophus . Rhinolophidae has sometimes been considered to include members of the family Hipposideridae (Old World leaf-nosed bats, with 82 species in 9 genera) as well, with the two groups being considered subfamilies (Rhinolophinae and Hipposiderinae). There is little question that these two groups of bats are closely related, but current understanding suggests the two groups should be recognized as families.

Rhinolophids inhabit temperate and tropical regions of southern Europe, Africa, Asia, parts of Australasia, and many Pacific islands. All species are insectivorous, hawking insects in flight or gleaning them from surfaces. Their roost habits are diverse; some species are found in large colonies in caves, some prefer hollow trees; others sleep in the open, among the branches of trees. Members of northern populations may hibernate during the winter. Females of some rhinolophid species mate during the fall and store sperm over the winter, conceiving and gestating young beginning in the spring.

Geographic Range

Rhinolophids are widely distributed throughout both temperate and tropical regions of the Old World. They inhabit southern Europe, Africa, Asia, northern and eastern Australia, and many Pacific islands.

• Biogeographic Regions
• palearctic palearctic
  • native native
• oriental oriental
  • native native
• ethiopian ethiopian
  • native native
• australian australian
  • native native
• oceanic islands oceanic islands
  • native native

• Other Geographic Terms
• island endemic island endemic

Habitat

Rhinolophids are found in a variety of temperate, tropical and desert biomes at both high and low elevations. They forage both within forests and in open spaces. Their roosting habits are also diverse: rhinolophids use caves, tree holes, foliage, mines, and buildings. Species that hibernate may use different roost types in the summer and winter months. While a cave may be used for hibernation in the winter, a tree hole may be used as a summer roost.

• Habitat Regions
• temperate temperate
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• desert or dune desert or dune
• forest forest
• rainforest rainforest
• mountains mountains

• Other Habitat Features
• suburban suburban
• agricultural agricultural

Physical Description

All rhinolophids have leaf or spear-like protuberances on their noses. The projection beneath the nostrils is horse-shoe shaped and pronounced in rhinolophids. Echolocation calls are emitted through these nasal structures, which may serve to focus the sound. The ears of these bats vary in size and lack a tragus. Most rhinolophids are dull brown or reddish brown in color. Their fur has a tendency to become bleached, so some individuals may become a bright reddish-orange. They vary in size from small to moderately large (4 to 28 grams). Males may be slightly larger than females. Their wings are broad and rounded, making them highly maneuverable in flight in cluttered spaces.

Rhinolophids have distinctive premaxillae , with palatal branches only. The premaxillae on opposite sides of the skull are neither fused with each other nor are they fused with the maxillary bones. Rhinolophid skulls often have distinct sagittal and lambdoidal crests. The palate is unusually short due to deep indentations at both ends. The molars are dilambdodont , and the dental formula is 1/2, 1/1, 1-2/2-3, 3/3 = 28-32.

• Other Physical Features
• endothermic endothermic
• heterothermic heterothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike
• male larger

Reproduction

Although there is little or no information available describing specific mating systems within Rhinolophidae , a few inferences may be drawn from the patterns of association between males and females. Some species form small family groups, and monogamy may be the mating systems in these cases. Others form larger colonies, either of mixed or separate sexes. In bat families (e.g., Vespertilionidae ) that have been more extensively studied, this colony structure is often correlated with a promiscuous mating system. Some rhinolophids are solitary, it is not clear what mating systems are associated with these bats.

All temperate rhinolophids are monestrous, having only a single reproductive cycle per year. These species typically mate in the fall before entering hibernation and undergo either delayed fertilization or delayed implantation to ensure that their young are born in the following spring, when resources are abundant. Tropical rhinolophids are probably monestrous but may be polyestrous. Adult females give birth to one offspring per breeding cycle. Young reach independence several weeks after birth and become sexually mature by 2 years of age.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous
• delayed fertilization delayed fertilization
• delayed implantation delayed implantation

Parental care is provided exclusively by females in most rhinolophids (and in most bats in general). Males may provide some form of care or defense in those species that form family groups. Females that are near to giving birth bear a considerable burden; young may be up to 25% of the mother's weight when they are born. Heavily pregnant females are awkward flyers. Young are born in an altricial state, but develop rapidly. Females nurse their offspring for about a month before the young have learned to fly and hunt well enough to become independent. Juveniles may learn some aspects of foraging behaviors from their mothers. Females of many species of bats, including some rhinolophids, may use the same nursery roost site as their mothers when they have young of their own.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • male
    • female
• post-independence association with parents

Lifespan/Longevity

Rhinolophids, like many bats, can live exceptionally long lives for such small animals. The longest known lifespan of a wild rhinolophid is 30 years.

Behavior

Rhinolophids have broad, rounded wings that permit excellent maneuverability at very slow speeds. Many rhinolophids can hover in place, which is helpful when they are picking prey from the surfaces of leaves or out of spider webs. All rhinolophids also capture flying insects; many species do so while in continuous flight, but others search for insects as they hang from a perch and then make short pursuit flights when prey is detected. Upon capturing food, they land and wait for another insect to fly nearby. Even those bats that do not hunt from perches will land to consume an especially large insect. Most rhinolophids hunt either very close to the ground or within 6 meters of the ground.

While some species are solitary, most rhinolophids roost in colonies. They generally forage alone. These bats do not defend feeding territories, but do tend to use well-defined foraging territories. Rhinolophids are all nocturnal and are active later in the evening than many other groups of bats.

Horseshoe bats have a roosting posture that is unique among bats. Instead of hanging with their wings folded at their sides, they wrap their wings and tail membranes around their bodies, enshrouding themselves.

All rhinolophids in temperate regions hibernate during the winter. Even during the active season, these bats enter daily torpor to conserve energy. Some species and populations migrate seasonally.

• Key Behaviors
• flies
• nocturnal nocturnal
• motile motile
• migratory migratory
• sedentary sedentary
• hibernation hibernation
• daily torpor
• solitary solitary
• social social
• colonial colonial

Communication and Perception

All rhinolophids use echolocation as a primary means of navigating and finding food. Rhinolophid echolocation calls typically have two components: a constant frequency portion and a frequency-modulated sweep. The constant-frequency portion is about 20 milliseconds long. Unlike many other microchiropterans, rhinolophids can tolerate considerable overlap between outgoing calls and returning echoes. This tolerance allows them to spend more time calling, thus increasing their chances of detecting prey. Rhinolophids emit calls through their nasal passages, which lets them continue calling as they chew. Their echolocation calls are directed using motions of the head and the physical attributes of their complex noseleaves. The calls of many species have several harmonics, which increases their frequency range and thus the size distribution of detectable targets.

Vision, olfaction, and touch are also important to varying degrees in bats. Scent plays an important role in many social interactions, such as in mating and in mother-infant bonding. Scent glands are common in many bats (as they generally are in mammals).

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• pheromones pheromones

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• ultrasound ultrasound
• echolocation echolocation
• chemical chemical

Food Habits

These bats either catch insects in flight or take insects and spiders from surfaces. Rhinolophids typically forage near the ground or near dense foliage, which allows them to detect non-flying prey. Rhinolophids are capable of extremely maneuverable flight, including the ability to hover. Bats that are capable of hovering can exploit prey sources on surfaces, a resource most bat species cannot exploit. Species in this family may use regular, well-defined foraging areas.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods

Predation

Predation on bats generally appears to be low, and this probably is true for rhinolophids as well. Most knowledge of bat predators comes from anecdotal observation of predation events or bat remains in scat. Groups that are known to eat bats are owls and other birds of prey , many carnivores , other bats , snakes , and other opportunistic vertebrate scavengers that encounter an injured or juvenile bat. Bats are probably most vulnerable to predators while they roost or as they emerge in the evening to forage. Some predators (e.g., snakes or hawks) may wait near cave entrances at dusk, attacking bats as they emerge. Juvenile bats that cannot fly are also at risk if they fall to the ground and are not quickly retrieved by their mothers.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

All bats in the family Rhinolophidae eat only insects and other small arthropods. Their primary ecosystem function is probably to limit populations of insects and spiders. Bats harbor parasites such as fleas , mites and trematodes ; thus, rhinolophids also serve as a resource for parasites. Bats are not typically important prey for other animals, but they are preyed upon by nocturnal birds of prey and snakes.

Economic Importance for Humans: Positive

Rhinolophids are all insectivorous and are likely to control populations of insect pests. Large guano deposits can be harvested commercially for fertilizer.

• Positive Impacts
• produces fertilizer
• controls pest population

Economic Importance for Humans: Negative

Some rhinolophids may become household pests if they form large colonies in human dwellings. The buildup of guano from a large colony can produce a foul odor.

• Negative Impacts
• household pest

Conservation Status

Many bats are declining worldwide, and this is true for many rhinolophids as well (e.g., Rhinolophus hipposideros and Rhinolophus ferrumequinum ). Disturbance of roosts, particularly winter hibernacula, can threaten a large number of bats in a short time. Habitat destruction (e.g., the reduction of appropriate forest habitat) is also a problem. Many insectivorous species are threatend by widespread pesticide use. Individual bats can eat hundreds of insects in an evening. If those insects have ingested harmful chemicals, the bats may suffer as a result. The International Union for the Conservation of Nature and Natural Resources (IUCN) currently lists 5 species of rhinolophids as vulnerable, 6 as near threatened, 4 as endangerd, and 1 as critically endangered ( Rhinolophus hilli ). Data is insufficient to evaluate the status of many other species, so this may be an underestimate of the groups overall vulnerability.

Other Comments

The earliest rhinolophids in the fossil record are known from the Middle Eocene in Europe.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Matthew Wund (author), University of Michigan-Ann Arbor, Phil Myers (author), Museum of Zoology, University of Michigan-Ann Arbor.

References

Hill, J., J. Smith. 1984. Bats: A Natural History . Austin: University of Texas Press.

IUCN, 2004. "IUCN Red List of Threatened Species" (On-line). Accessed August 24, 2005 at www.iucnredlist.org .

Nowak, R. 1991. Horseshoe Bats. Pp. 253-256 in Walker's Mammals of the World , Vol. 1, 5th Edition. Baltimore: Johns Hopkins University Press.

Nowak, R. 1991. Old World Leaf Nosed Bats. Pp. 256-265 in Walker's Mammals of the World , Vol. 1, 5th Edition. Baltimore: Johns Hopkins University Press.

Simmons, N., T. Conway. 1997. "Rhinolophidae" (On-line). Tree of Life web project. Accessed February 08, 2009 at http://tolweb.org/Rhinolophidae/16126 .

Teeling, E., O. Madsen, R. van den Bussche, W. de Jong, M. Stanhope, M. Springer. 2002. Microbat monophyly and the convergent evolution of a key innovation in old world rhinolophoid microbats. Proceedings of the National Academy of Sciences of the United States of America , 99/3: 1431-1436.

Vaughan, T., J. Ryan, N. Czaplewski. 2000. Mammalogy, 4th Edition . Toronto: Brooks Cole.

Wilson, D., D. Reeder. 2005. Mammal Species of the World, 3rd edition . Baltimore: Johns Hopkins University Press. Accessed February 07, 2009 at http://www.bucknell.edu/msw3/ .