| Four-horned antelope | |
|---|---|
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| Bondla Wildlife Sanctuary, India | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Family: | Bovidae |
| Subfamily: | Bovinae |
| Tribe: | Boselaphini |
| Genus: | Tetracerus Leach, 1825 |
| Species: | T. quadricornis |
| Binomial name | |
| Tetracerus quadricornis (Blainville, 1816) | |
| Subspecies | |
T. q. iodes(Hodgson, 1847) | |
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| Range map of the four-horned antelope | |
| Synonyms[3] | |
List
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Thefour-horned antelope (Tetracerus quadricornis), also calledchousingha, is a smallbovidantelope native tocentral,South andWestern India, along with a smaller population inNepal. Thesole member of thegenusTetracerus, the chousingha was firstscientifically described in 1816 by FrenchzoologistHenri Marie Ducrotay de Blainville. Three regionalsubspecies are currently recognised. The four-horned antelope has a yellowish-tan, sometimes reddish or goldenrod coat. It is slender with thin legs and a short tail. It stands nearly 55–64 cm (22–25 in) at the shoulder and weighs about 17–22 kg (37–49 lb). Its fourhorns are unique amongantelopes and distinguish it from most other bovids. The longer pair of straight, spike-like horns is atop its head between the ears, while the other, shorter pair is on the forehead; itsposterior horns are always longer than theanterior horns, which may even present as merely fur-covered "studs". While the posterior horns measure 8–12 cm (3.1–4.7 in), the anterior ones are usually 2–5 cm (0.79–1.97 in) long.
The four-horned antelope isdiurnal (active mainly during the day) and typically solitary by nature, though some antelope may form loose groups of three to five animals, usually one or more adults, possibly accompanied by calves. This elusive antelope feeds on grasses, herbs, shrubs, foliage, flowers and fruits. It needs to drink water frequently; as such it stays in places near water sources. The breeding behaviour of the four-horned antelope has not been well studied. The age at which they reachsexual maturity and the season when mating occurs have not been understood well.Gestation lasts about eight months, following which one or two calves are born. They are kept concealed for the first few weeks of their birth. The young remain with the mother for about a year.
Four-horned antelopes tend to inhabit areas with significant grass cover or heavy undergrowth, and avoid human settlements or the presence of dogs. Once more common throughoutdeciduous forests in India, the four-horned antelope now occurs in disjunct, fragmented populations, with genetic "bottlenecking" (e.g.inbreeding) becoming a potential threat to the stability of future populations that do not intermingle duringmating seasons. The four-horned antelope is threatened by the loss of its natural habitat due toagricultural expansion. Because of its four-horned skull and its horns it was historically a target fortrophy hunters. It is presently listed asvulnerable on theIUCN Red List.
Thescientific name of the four-horned antelope isTetracerus quadricornis. Thegeneric nameTetracerus is the combination of twoGreek words:tetra meaning "four"[4]: 351 andkeras meaning "horn".[4]: 422 Thespecific namequadricornis is derived from twoLatin words:quattuor meaning "four"[4]: 351 andcornu "horn".[4]: 421 The four-horned antelope is known by several vernacular names:chausingha,chowsingha,chousingha (Hindi for "four horns"),doda,ghutri (mainly in central India) (Hindi);kondu kuri (Kannada);chauka (Nepalese);nari komboo marn (Tamil).[3]
The four-horned antelope is the sole member of thegenusTetracerus, and is placed under thefamilyBovidae. The species was firstdescribed by French zoologistHenri Marie Ducrotay de Blainville in 1816.[5] The four-horned antelope has only one other relative in the tribeBoselaphini, thenilgai (Boselaphus tragocamelus).[3] The Boselaphini have horns with a keel on the front and lack rings as found in other antelope groups.[6]
Theauthority forTetracerus is variously indicated according to interpretations of theInternational Code of Zoological Nomenclature. The name was first published in an 1825 publication by English naturalistThomas Hardwicke but cited the English zoologistWilliam Elford Leach – probably by an editor – as the authority in a footnote at the end of the publication.[7]Philip Sclater andOldfield Thomas listed Hardwicke as the genus authority by virtue of his being the author of the publication. However, Leach is now identified as the appropriate authority based on Article 50.1.1 of the Zoological Code.[3]
A 1992phylogenetic study showed a strong possibility of aclade consisting of Boselaphini,Bovini andTragelaphini. Bovini consists of the generaBubalus,Bos,Pseudoryx (saola),Syncerus (African buffalo),Bison and theextinctPelorovis. Tragelaphini consists of two genera:Taurotragus (eland) andTragelaphus. Boselaphini and Tragelaphini were predicted to be close;[8] this was seconded by a similar study in 1999.[9] The following cladogram is based on the 1992 study:[8]
Colin Groves (2003) recognizes three subspecies of the four-horned antelope on the basis of distribution and physical characteristics such ascoat colour, body size and the number of horns:[5][10]
Though Boselaphini has no African representation today,[13]fossil evidence supports its presence in the continent as early as the lateMiocene – the two living antelopes of this tribe, in fact, have been found to have a closer relationship with the earliest bovids (likeEotragus species) than do the other bovids.[14][15] This tribe originated at least 8.9 Mya, in much the same area where the four-horned antelope occurs today, and may represent the most "primitive" of all living bovids, having changed the least since the origins of the family.[16] The extant and extinct boselaphine forms show similar development of the horn cores (the central bony part of the horn).[17] It is thought that ancestral bovids had adiploidchromosome number of 58 which has reduced inTetracerus to 38 through a process of concatenation of some chromosomes.[18]
Fossils ofProtragocerus labidotus andSivoreas eremita dating back to the late Miocene have been discovered in the Ngorora formation (Kenya).[19] Fossils from the same period have also been excavated in the easternMediterranean region.[20] Other Miocene fossils of boselaphines discovered are ofMiotragocerus,Tragocerus andTragoportax. Fossils ofMiotragoceros are not apparent in Africa (onlyM. cyrenaicus has been reported from the continent), but have significant presence in theShiwalik Hills in India and Pakistan, as do severalTragoportax species. A 2005 study suggested the migration ofMiotragoceros to eastern Asia around 8 Mya.[21] Alan W. Gentry of theNatural History Museum reported the presence of another boselaphine,Mesembriportax, fromLangebaanweg (South Africa).[22]
Evidence of early humans hunting four-horned antelope during theMesolithic period (5,000 to 8,000 years ago) have been found in the Kurnool caves of southern India[23] and similar evidence has been found from theChalcolithic period (3,000 years ago) in Orissa, eastern India.[24]
The four-horned antelope is one of the smallest Asian bovids. The number of its horns distinguishes it from most of the other bovids, that have two horns[25] The four-horned antelope stands 55–64 centimetres (22–25 in) at the shoulder and weighs 17–22 kilograms (37–49 lb); the head-and-body length is typically between 80 and 110 centimetres (31 and 43 in).[26]Sexual dimorphism is not very notable, though only males possess horns.[3]
Slender with thin legs and a short tail, the four-horned antelope has a yellowish brown to reddish coat. The underparts and the insides of the legs are white. Facial features include black markings on themuzzle and behind the ears. A black stripe marks the outer surface of each leg. Females have four teats far back on the abdomen.[3] The hair feels coarse, more like that of adeer than the glossy hair typical ofantelopes.[27] Thefetlocks are marked with white patches.[27]
One pair of horns is located between the ears, and the other on the forehead. Theposterior horns are always longer than the anterior horns, which might be mere fur-covered studs. While the posterior horns each measures 8–12 centimetres (3.1–4.7 in), the anterior ones measure 2–5 centimetres (0.79–1.97 in).[27][28][29] Horns emerge at 10 to 14 months.[3] According to Groves, anterior horns show the poorest development in the subspeciesT. q. subquadricornutus. These horns measure nearly 4.5–5 centimetres (1.8–2.0 in) inT. q. quadricornis, and nearly 1.5–2.5 centimetres (0.59–0.98 in) inT. q. iodes. The posterior horn lengths for the subspecies recorded by him were: 8–10 centimetres (3.1–3.9 in) forT. q. quadricornis, 6.5–7.5 centimetres (2.6–3.0 in) inT. q. iodes and 1.8–2 centimetres (0.71–0.79 in) inT. q. subquadricornutus.[10]
The four-horned antelope differs greatly from the nilgai in colour, is much smaller and has an extra pair of horns. The nilgai is nearly nine times heavier and two times taller than the four-horned antelope. Two deer species, theIndian muntjac and theIndian hog deer, can be confused with this antelope. The four-horned antelope, however, lacks theirantlers.[3] Thechinkara, agazelle, can be told apart by its light brown coat and larger, ringed horns.[30]
The four-horned antelope is diurnal (active mainly during the day), though it mainly rests orruminates in dense undergrowth at noon.[31] Though solitary by nature, the four-horned antelope may form loose groups of three to five. Groups consist of one or more adults, sometimes accompanied by juveniles. Males and females hardly interact, except in the mating season.[32]
The antelope is shy and elusive. When alarmed, it stands motionless and may nervously leap away from the danger or even sprint. It often conceals itself in tall grasses to escape predators.[27] The use of alarm calls to alert others is not common because the antelope tries to avoid the attention of predators. However, in extreme cases, these calls may be used to warn predators that they have been identified. Adultsmark vegetation in theirterritories with a colourless secretion ofpreorbital glands, that soon condenses to form a white film. They maintain multiplelatrine sites where piles of their pellet droppings are formed by regular use.[31] Latrine sites can be confused with those of the barking deer but the pellets are longer and larger in four-horned antelopes.[33] Submissivedisplay consists of shrinking the body, lowering the head and pulling the ears back.[31] Predators of four-horned antelopes include tigers,[34]leopards, anddholes.[35]
The four-horned antelope feeds on grasses, herbs, shrubs, foliage, flowers and fruits. A study inMudumalai National Park (Tamil Nadu, India) showed that the antelope prefers grass species of the familyCyperaceae; generaAxonopus,Cynodon,Digitaria,Echinochloa,Panicum,Sehima andSporobolus; and the speciesImperata cylindrica,Ottochloa nodosa,Pseudanthistria umbellata andThemeda cymbaria. The shrubGrewia hirsuta is frequently eaten. Preferred herbs includeHelichrysum,Indigofera andTinospora species andLeucas aspera. The four-horned antelope feeds on the leaves of trees such asCordia wallichii,Emblica officinalis,Randia dumetorum andZizyphus xylopyrus. Grasses comprise nearly 29 percent of the diet, followed by foliage from trees (nearly nine percent). Grass andbrowse were consumed in nearly equal proportions.[32] A study in thePanna National Park (Madhya Pradesh, India) showed preference forZizyphus mauritiana,Acacia nilotica,A. leucophloea andA. catechu.Babool flowers were frequently eaten. The antelope often associates withlangurs under fruiting trees, just aschital frequently do. Interaction with chital, asympatric species, was infrequent.[31] The antelope is wary when feeding, often raising its head and looking about its vicinity.[31] The four-horned antelope needs to drink water frequently; as such it stays in places near water sources.[27]
Breeding behaviour of the four-horned antelope has not been well studied. The age at which sexual maturity is gained is doubted; two captive females had their first parturition at less than two years.[3] The breeding season in Panna National Park probably lasts from May to July,[31] and from June to August in Mudumalai National Park.[32] The male approaches the female in a relaxed gait, giving out low coughs. The two may kneel and push against each other with the necks intertwined. The male makes a few short mounting attempts; the female may be foraging all the while without any reaction.[31]Gestation lasts about eight months, followed by the birth of one or two calves. The newborn has a head-and-body length of 42 to 46 cm (17 to 18 in), and weighs 0.7 to 1.1 kg (1.5 to 2.4 lb). Juveniles are kept concealed for the first few weeks of birth. Births in Mudumalai National Park peak from February to April. Juveniles remain with their mothers for about a year.[3]
The four-horned antelope is confined to theIndian subcontinent, occurring widely in disjunct and small populations. It ranges from the foothills of theHimalayas in the north to theDeccan Plateau in the south. Most of the existing populations lives in India, and lower numbers in adjoining Nepal.[1] Observations have been logged from the states ofAndhra Pradesh, Chhattisgarh,Gujarat, Karnataka,Madhya Pradesh, Maharashtra andTelangana oniNaturalist.org'sbiodiversity database.[36]It inhabits open,dry deciduous forests in flat to hilly terrain.[37][38] It prefers areas close to water that are covered with grasses or heavy undergrowth, for security. As manyUngulates are skittish by nature, the chousingha, notably, generally keeps away from human settlements; research suggests that human activities, construction, andferal dogs all adversely affect chousingha numbers, thus areas of less human habitation support more stable chousingha populations.[citation needed]
The four-horned antelope was once common throughoutdeciduous forests in India, but the population has declined over time. In 2001, it was estimated to comprise about 10,000 mature individuals, with a decreasing trend.[37][1] Numbers inGir National Park were estimated at 256 individuals in 1974; later estimates at waterholes in the same locations put them slightly over 1,000 individuals, and a population density of above 0.7 individuals per 1 km2 (0.39 sq mi) was considered to be healthy.[39]
The four-horned antelope is classified asvulnerable on theIUCN Red List. It is threatened by the loss of its natural habitat due to agricultural expansion.[1] Its four-horned skull and the horns have been targeted bytrophy hunters.[40]
The four-horned antelope is protected under Schedule I of the IndianWildlife Protection Act of 1972; the population in Nepal is listed inCITES Appendix III.[1][2]Major protected areas in India where four-horned antelopes occur include:[41]
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Media related toTetracerus quadricornis at Wikimedia Commons
Data related toTetracerus quadricornis at Wikispecies