Four-horned antelope
The four-horned antelope, also called chousingha, is a small bovid antelope native to central, South and Western India, along with a smaller population in Nepal. The sole member of the genus Tetracerus, the chousingha was first scientifically described in 1816 by French zoologist Henri Marie Ducrotay de Blainville. Three regional subspecies 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 at the shoulder and weighs about. Its four horns are unique among antelopes 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; its posterior horns are always longer than the anterior horns, which may even present as merely fur-covered "studs". While the posterior horns measure, the anterior ones are usually long.
The four-horned antelope is diurnal 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 reach sexual 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 throughout deciduous forests in India, the four-horned antelope now occurs in disjunct, fragmented populations, with genetic "bottlenecking" becoming a potential threat to the stability of future populations that do not intermingle during mating seasons. The four-horned antelope is threatened by the loss of its natural habitat due to agricultural expansion. Because of its four-horned skull and its horns it was historically a target for trophy hunters. It is presently listed as vulnerable on the IUCN Red List.
Etymology
The scientific name of the four-horned antelope is Tetracerus quadricornis. The generic name Tetracerus is the combination of two Greek words: tetra meaning "four" and keras meaning "horn". The specific name quadricornis is derived from two Latin words: quattuor meaning "four" and cornu "horn". The four-horned antelope is known by several vernacular names: chausingha, chowsingha, chousingha, doda, ghutri ; kondu kuri ; chauka ; nari komboo marn.Taxonomy and phylogeny
The four-horned antelope is the sole member of the genus Tetracerus, and is placed under the family Bovidae. The species was first described by French zoologist Henri Marie Ducrotay de Blainville in 1816. The four-horned antelope has only one other relative in the tribe Boselaphini, the nilgai. The Boselaphini have horns with a keel on the front and lack rings as found in other antelope groups.The authority for Tetracerus is variously indicated according to interpretations of the International Code of Zoological Nomenclature. The name was first published in an 1825 publication by English naturalist Thomas Hardwicke but cited the English zoologist William Elford Leach – probably by an editor – as the authority in a footnote at the end of the publication. Philip Sclater and Oldfield 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.
A 1992 phylogenetic study showed a strong possibility of a clade consisting of Boselaphini, Bovini and Tragelaphini. Bovini consists of the genera Bubalus, Bos, Pseudoryx, Syncerus, Bison and the extinct Pelorovis. Tragelaphini consists of two genera: Taurotragus and Tragelaphus. Boselaphini and Tragelaphini were predicted to be close; this was seconded by a similar study in 1999. The following cladogram is based on the 1992 study:
Colin Groves recognizes three subspecies of the four-horned antelope on the basis of distribution and physical characteristics such as coat colour, body size and the number of horns:
- T. q. iodes : distributed north of the Ganges in Nepal
- T. q. quadricornis : distributed in peninsular India
- T. q. subquadricornutus distributed in the Western Ghats and southern India
Evolution
Fossils of Protragocerus labidotus and Sivoreas eremita dating back to the late Miocene have been discovered in the Ngorora formation. Fossils from the same period have also been excavated in the eastern Mediterranean region. Other Miocene fossils of boselaphines discovered are of Miotragocerus, Tragocerus and Tragoportax. Fossils of Miotragoceros are not apparent in Africa, but have significant presence in the Shiwalik Hills in India and Pakistan, as do several Tragoportax species. A 2005 study suggested the migration of Miotragoceros to eastern Asia around 8 Mya. Alan W. Gentry of the Natural History Museum reported the presence of another boselaphine, Mesembriportax, from Langebaanweg.
Evidence of early humans hunting four-horned antelope during the Mesolithic period have been found in the Kurnool caves of southern India and similar evidence has been found from the Chalcolithic period in Orissa, eastern India.
Description
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 The four-horned antelope stands at the shoulder and weighs ; the head-and-body length is typically between. Sexual dimorphism is not very notable, though only males possess horns.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 the muzzle and behind the ears. A black stripe marks the outer surface of each leg. Females have four teats far back on the abdomen. The hair feels coarse, more like that of a deer than the glossy hair typical of antelopes. The fetlocks are marked with white patches.
One pair of horns is located between the ears, and the other on the forehead. The posterior horns are always longer than the anterior horns, which might be mere fur-covered studs. While the posterior horns each measures, the anterior ones measure. Horns emerge at 10 to 14 months. According to Groves, anterior horns show the poorest development in the subspecies T. q. subquadricornutus. These horns measure nearly in T. q. quadricornis, and nearly in T. q. iodes. The posterior horn lengths for the subspecies recorded by him were: for T. q. quadricornis, in T. q. iodes and in T. q. subquadricornutus.
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, the Indian muntjac and the Indian hog deer, can be confused with this antelope. The four-horned antelope, however, lacks their antlers. The chinkara, a gazelle, can be told apart by its light brown coat and larger, ringed horns.
Ecology and behaviour
The four-horned antelope is diurnal, though it mainly rests or ruminates in dense undergrowth at noon. 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.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. 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. Adults mark vegetation in their territories with a colourless secretion of preorbital glands, that soon condenses to form a white film. They maintain multiple latrine sites where piles of their pellet droppings are formed by regular use. Latrine sites can be confused with those of the barking deer but the pellets are longer and larger in four-horned antelopes. Submissive display consists of shrinking the body, lowering the head and pulling the ears back. Predators of four-horned antelopes include tigers, leopards, and dholes.