Horseshoe bat
Horseshoe bats | |
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Lesser horseshoe bat (Rhinolophus hipposideros) with blue metallic identification band on left wing | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Chiroptera |
Family: | Rhinolophidae Gray, 1825 |
Subfamily: | Rhinolophinae Gray, 1825 |
Genus: | Rhinolophus Lacépède, 1799 |
Type species | |
Vespertilio ferrum-equinum Schreber, 1774
| |
Species | |
Horseshoe bats are bats in the family Rhinolophidae. In addition to the single living genus, Rhinolophus, which has about 106 species, the extinct genus Palaeonycteris has been recognized. Horseshoe bats are closely related to the Old World leaf-nosed bats, family Hipposideridae, which have sometimes been included in Rhinolophidae. The horseshoe bats are divided into six subgenera and many species groups. The most recent common ancestor of all horseshoe bats lived 34–40 million years ago, though it is unclear where the geographic roots of the family are, and attempts to determine its biogeography have been indecisive. Their taxonomy is complex, as genetic evidence shows the likely existence of many cryptic species, as well as species recognized as distinct that may have little genetic divergence from previously recognized taxa. They are found in the Old World, mostly in tropical or subtropical areas, including Africa, Asia, Europe, and Oceania.
Horseshoe bats are considered small or medium-sized microbats, weighing 4–28 g (0.14–0.99 oz), with forearm lengths of 30–75 mm (1.2–3.0 in) and combined lengths of head and body of 35–110 mm (1.4–4.3 in). The fur, long and smooth in most species, can be reddish-brown, blackish, or bright orange-red. They get their common name from their large nose-leafs, which are shaped like horseshoes. The nose-leafs aid in echolocation; horseshoe bats have highly sophisticated echolocation, using constant frequency calls at high-duty cycles to detect prey in areas of high environmental clutters. They hunt insects and spiders, swooping down on prey from a perch, or gleaning from foliage. Little is known about their mating systems, but at least one species is monogamous, while another is polygynous. Gestation is approximately seven weeks and one offspring is produced at a time. A typical lifespan is six or seven years, but one greater horseshoe bat lived more than thirty years.
Horseshoe bats are relevant to humans in some regions as a source of disease, as food, and for
They are hunted for food in several regions, particularly sub-Saharan Africa, but also Southeast Asia. Some species or their guano are used in traditional medicine in Nepal, India, Vietnam, and Senegal.
Taxonomy and evolution
Taxonomic history
Rhinolophus was first described as a genus in 1799 by French naturalist
Attempts were made to divide Rhinolophus into other genera. In 1816, English zoologist William Elford Leach proposed the genus name Phyllorhina; Gray proposed Aquias in 1847 and Phyllotis in 1866; and German naturalist Wilhelm Peters proposed Coelophyllus in 1867. In 1876, Irish zoologist George Edward Dobson returned all Asiatic horseshoe bats to Rhinolophus, additionally proposing the subfamilies Phyllorhininae (for the hipposiderids) and Rhinolophinae. American zoologist Gerrit Smith Miller Jr. further divided the hipposiderids from the horseshoe bats in 1907, recognizing Hipposideridae as a distinct family.[2]: xii Some authors have considered Hipposideros and associated genera as part of Rhinolophidae as recently as the early 2000s,[9] though they are now most often recognized as a separate family.[10][11] After the split into Rhinolophidae and Hipposideridae, further divisions were proposed for Rhinolophus, with Rhinolphyllotis in 1934 and Rhinomegalophus in 1951, though both additional genera were returned to Rhinolophus.[2]: xii
Danish mammalogist Knud Andersen was the first to propose species groups for Rhinolophus, doing so in 1905. Species groups are a way of clustering species to reflect evolutionary relationships. He recognized six species groups: R. simplex (now R. megaphyllus), R. lepidus, R. midas (now R. hipposideros), R. philippinensis, R. macrotis, and R. arcuatus. The species have been frequently rearranged among the groups as new groups are added, new species are described, and relationships among species are revised.[2]: xiii Fifteen species groups were given by Csorba and colleagues in 2003.[2][12] Various subgenera have been proposed as well, with six listed by Csorba et al. in 2003: Aquias, Phyllorhina, Rhinolophus, Indorhinolophus, Coelophyllus, and Rhinophyllotis.[2]: xvi Informally, the rhinolophids can be split into two major clades: the mostly African clade, and the mostly Oriental clade.[9]
Evolutionary history
The most recent common ancestor of Rhinolophus lived an estimated 34–40 million years ago,[13] splitting from the hipposiderid lineage during the Eocene.[9] Fossilized horseshoe bats are known from Europe (early to mid-Miocene, early Oligocene), Australia (Miocene), and Africa (Miocene and late Pliocene).[14] The biogeography of horseshoe bats is poorly understood. Various studies have proposed that the family originated in Europe, Asia, or Africa. A 2010 study supported an Asian or Oriental origin of the family, with rapid evolutionary radiations of the African and Oriental clades during the Oligocene.[9] A 2019 study found that R. xinanzhongguoensis and R. nippon, both Eurasian species, are more closely related to African species than to other Eurasian species, suggesting that rhinolophids may have a complex biogeographical relationship with Asia and the Afrotropics.[13]
A 2016 study using
Chiroptera
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Rhinolophidae is represented by one extant genus, Rhinolophus. Both the family and the genus are confirmed as
The second genus in Rhinolophidae is the extinct Palaeonycteris, with the type species Palaeonycteris robustus.[15] Palaeonycteris robustus lived during the Lower Miocene and its fossilized remains were found in Saint-Gérand-le-Puy, France.[16][17]
Description
Appearance
Horseshoe bats are considered small or medium
Like most bats, horseshoe bats have two mammary glands on their chests. Adult females additionally have two teat-like projections on their abdomens, called pubic nipples or false nipples, which are not connected to mammary glands. Only a few other bat families have pubic nipples, including Hipposideridae, Craseonycteridae, Megadermatidae, and Rhinopomatidae; they serve as attachment points for their offspring.[19] In a few horseshoe bat species, males have a false nipple in each armpit.[10]
Head and teeth
All horseshoe bats have large, leaf-like protuberances on their noses, which are called
Postcrania
Several bones in its
Biology and ecology
Echolocation and hearing
Horeshoe bats have very small eyes and their field of vision is limited by their large nose-leafs; thus, vision is unlikely to be a very important sense. Instead, they use echolocation to navigate,[14] employing some of the most sophisticated echolocation of any bat group.[24] To echolocate, they produce sound through their nostrils. While some bats use frequency-modulated echolocation, horseshoe bats use constant-frequency echolocation (also known as single-frequency echolocation).[25] They have high duty cycles, meaning that when individuals are calling, they are producing sound more than 30% of the time. The use of high duty, constant-frequency echolocation aids in distinguishing prey items based on size. These echolocation characteristics are typical of bats that search for moving prey items in cluttered environments full of foliage.[24] They echolocate at particularly high frequencies for bats, though not as high as hipposiderids relative to their body sizes, and the majority concentrate most of the echolocation energy into the second harmonic. The king horseshoe bat (R. rex) and the large-eared horseshoe bat (R. philippensis) are examples of outlier species that concentrate energy into the first harmonic rather than the second.[26] Their highly furrowed nose-leafs likely assist in focusing the emission of sound, reducing the effect of environmental clutter.[25] The nose-leaf in general acts like a parabolic reflector, aiming the produced sound while simultaneously shielding the ear from some of it.[10]
Horseshoe bats have sophisticated senses of hearing due to their well-developed cochlea,[10] and are able to detect Doppler-shifted echoes. This allows them to produce and receive sounds simultaneously.[2]: xi Within horseshoe bats, there is a negative relationship between ear length and echolocation frequency: Species with higher echolocation frequencies tend to have shorter ear lengths.[26] During echolocation, the ears can move independently of each other in a "flickering" motion characteristic of the family, while the head simultaneously moves up and down or side to side.[10]
Diet and foraging
Horseshoe bats are insectivorous, though consume other arthropods such as
They have especially small and rounded wingtips, low wing loading (meaning they lave large wings relative to body mass), and high camber. These factors give them increased agility, and they are capable of making quick, tight turns at slow speeds.[27]: 361 Relative to all bats, horseshoe bat wingspans are typical for their body sizes, and their aspect ratios, which relate wingspan to wing area, are average or lower than average. Some species, like Rüppell's horseshoe bat (R. fumigatus), Hildebrandt's horseshoe bat, Lander's horseshoe bat (R. landeri), and Swinny's horseshoe bat (R. swinnyi), have particularly large total wing area, though most horseshoe bat species have average wing area.[27]: 387
Reproduction and life cycle
The mating systems of horseshoe bats are poorly understood. A review in 2000 noted that only about 4% of species had published information about their mating systems; along with the
Behavior and social systems
Various levels of sociality are seen in horseshoe bats. Some species are solitary, with individuals roosting alone, while others are highly colonial, forming aggregations of thousands of individuals.[2]: xi The majority of species are moderately social. In some species, the sexes segregate annually when females form maternity colonies, though the sexes remain together all year in others. Individuals hunt solitarily.[18] Because their hind limbs are poorly developed, they cannot scuttle on flat surfaces nor climb adeptly like other bats.[14][10]
Horseshoe bats enter torpor to conserve energy. During torpor, their body temperature drops to as low as 16 °C (61 °F) and their metabolic rates slow.[32] Torpor is employed by horseshoe bats in temperate, sub-tropical, and tropical regions.[33] Torpor has a short duration; when torpor is employed consistently for days, weeks, or months, it is known as hibernation.[34] Hibernation is used by horseshoe bats in temperate regions during the winter months.[33]
Predators and parasites
Overall, bats have few natural predators.
Horseshoe bats have a variety of internal and external
Range and habitat
Horseshoe bats have a mostly
Relationship to humans
As disease reservoirs
Bat species | No. SARSr-CoVs |
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Chinese rufous horseshoe bat | 30
|
Greater horseshoe bat | 9
|
Big-eared horseshoe bat | 2
|
Least horseshoe bat | 2
|
Intermediate horseshoe bat | 1
|
Blasius's horseshoe bat | 1
|
Stoliczka's trident bat | 1
|
Wrinkle-lipped free-tailed bat | 1
|
Horseshoe bats are of particular interest to public health and zoonosis as a source of coronaviruses.
Following the
After the SARS outbreak, the least horseshoe bat (R. pusillus) was seropositive, the greater horseshoe bat tested positive for the virus only, and the big-eared horseshoe bat (R. macrotis), Chinese rufous horseshoe bat (R. sinicus), and Pearson's horseshoe bat (R. pearsoni) were both seropositive and tested positive for the virus.[47][49] The bats' viruses were highly similar to SARS-CoV, with 88–92% similarity.[1] Intraspecies diversity of SARS-like coronaviruses appears to have arisen in Rhinolophus sinicus by homologous recombination.[50] R. sinicus likely harbored the direct ancestor of SARS-CoV in humans. Though horseshoe bats appeared to be the natural reservoir of SARS-related coronaviruses, humans likely became sick through contact with infected masked palm civets, which were identified as intermediate hosts of the virus.[1]
During the period from 2003 to 2018, forty-seven SARS-related coronaviruses were detected in bats, forty-five in horseshoe bats. Thirty SARS-related coronaviruses were from Chinese rufous horseshoe bats, nine from greater horseshoe bats, two from big-eared horseshoe bats, two from the least horseshoe bat, and one each from the intermediate horseshoe bat (R. affinis), Blasius's horseshoe bat (R. blasii), Stoliczka's trident bat (Aselliscus stoliczkanus), and the wrinkle-lipped free-tailed bat (Chaerephon plicata).[47]
In the market in Wuhan where the SARS-CoV-2 was detected, 96% had a similarity to a virus isolated from the intermediate horseshoe bat. Research on the evolutionary origins of SARS-CoV-2[51] indicates that bats were the natural reservoirs of SARS-CoV-2. It is yet unclear how the virus was transmitted to humans, though an intermediate host may have been involved. It was once believed to be the Sunda pangolin,[52] but a July 2020 publication found no evidence of transmission from pangolins to humans.[51]
Other viruses
They are also associated with viruses like
As food and medicine
Microbats are not hunted nearly as intensely as megabats: only 8% of insectivorous species are hunted for food, compared to half of all megabat species in the Old World tropics. Horseshoe bats are hunted for food, particularly in sub-Saharan Africa. Species hunted in Africa include the halcyon horseshoe bat (R. alcyone), Guinean horseshoe bat (R. guineensis), Hill's horseshoe bat (R. hilli), Hills' horseshoe bat (R. hillorum), Maclaud's horseshoe bat (R. maclaudi), the Ruwenzori horseshoe bat, the forest horseshoe bat (R. silvestris), and the Ziama horseshoe bat (R. ziama). In Southeast Asia, Marshall's horseshoe bat (R. marshalli) is consumed in Myanmar and the large rufous horseshoe bat (R. rufus) is consumed in the Philippines.[56]
The
Conservation
As of 2023, the
- Critically endangered: 1 species (Hill's horseshoe bat)
- Endangered: 13 species
- Vulnerable: 5 species
- Near threatened: 9 species
- Least concern: 51 species
- Data deficient: 15 species
Like all cave-roosting bats, cave-roosting horseshoe bats are vulnerable to disturbance of their cave habitats. Disturbance can include mining bat guano, quarrying limestone, and cave tourism.[46]
References
- ^ PMID 17326933.
- ^ ISBN 9780953604913.
- ^ Gray, J. E. (1825). "An attempt at a division of the family Vespertilionidae into groups". The Zoological Journal. 2: 242.
- ^ ISBN 9780231528535.
- PMID 22984399.
- ^ "Family Rhinolophidae". Mammal Species of the World. Bucknell University. Retrieved 23 July 2020.
- PMID 11353869.
- ^ S2CID 3318167.
- ^ PMID 19766726.
- ^ ISBN 9781408189962.
- ^ Wilson, Don E.; Reeder, DeeAnn M., eds. (2005). "Family Hipposideridae". Mammal Species of the World (3rd ed.). Bucknell University. Retrieved 23 July 2020.
- S2CID 86009452.
- ^ PMID 31434566.
- ^ ISBN 978-0787657895.
- ^ Palmer, T. S. (1904). "A List of the Genera and Families of Mammal". North American Fauna (23): 503.
- ^ Lydekker, Richard (1885). Catalogue of the Fossil Mammalia in the British Museum, (Natural History): The orders Primates, Chiroptera, Insectivora, Carnivora, and Rodentia. Order of the Trustees. p. 13.
- .
The sole fossil genus, Palaeonycteris, is known from the Miocene of Europe (Heller 1936; Sigb and Legendre 1983; Hand 1984; cf. Simpson 1945 and Hall 1989)
- ^ ISBN 978-0-8018-4986-2.
- ^ Simmons, N. B. (1993). "Morphology, function, and phylogenetic significance of pubic nipples in bats (Mammalia, Chiroptera)" (PDF). American Museum Novitates (3077).
- ^ a b c Hall, Leslie (1989). "Rhinolophidae". In Walton, D.W.; Richardson, B.J. (eds.). Fauna of Australia (PDF). AGPS Canberra.
- ^ JSTOR 1380461.
- ISBN 9780323151191.
- PMID 19766726.
- ^ PMID 16701491.
- ^ PMID 22279156.
- ^ .
- ^ .
- .
- S2CID 90531252.
- ISBN 9780121956707.
- ISBN 9781408189962.
- hdl:10072/37379.
- ^ PMID 21700575.
- ISBN 9780191548727.
- PMID 23516436.
- .
- ^ García, A. M.; Cervera, F.; Rodríguez, A. (2005). "Bat predation by long-eared Owls in mediterranean and temperate regions of southern Europe" (PDF). Journal of Raptor Research. 39 (4): 445–453.
- S2CID 92282216.
- .
- S2CID 92844287.
- S2CID 7173658.
- PMID 27286701.
- S2CID 85527706.
- S2CID 90530235.
- PMID 23327008.
- ^ ISBN 978-3-319-25218-6.
- ^ PMID 30844511.
- ^ "Novel Coronavirus (2019-nCoV) Situation Report" (PDF). World Health Organization. 11 February 2020. Retrieved 15 February 2020.
- PMID 17451830.
- PMID 20016037
- ^ S2CID 220809302.
- PMID 32226946.
Evidence from the sequence analyses clearly indicates that the reservoir host of the virus was a bat, probably a Chinese or Intermediate horseshoe bat, and it is probable that, like SARS-CoV, an intermediate host was the source of the outbreak.
- ISBN 9781119150046.
- S2CID 32814428.
- PMID 23408889.
- S2CID 130038936.
- S2CID 146308445.
- ^ Riccucci, M. (2012). "Bats as materia medica: An ethnomedical review and implications for conservation". Vespertillio. 16 (16): 249–270.
- ^ "Taxonomy=Rhinolophidae". IUCN. Retrieved 28 December 2023.