An antelope is a member of a number of even-toed ungulate species indigenous to various regions in Africa and Eurasia. Antelopes comprise a wastebasket taxon (miscellaneous group) within the rare family Bovidae, encompassing those Old World species that are not cattle, sheep, buffalo, bison, or goats; even so, antelope are generally more deer-like than other bovids. A group of antelope is called a herd.
The 91 antelope species, most of which are native to Africa, occur in about 30 genera. The classification of tribes or subfamilies within Bovidae is still a matter of debate, with several alternative systems proposed.
Antelope are not a cladistic or taxonomically defined group. The term is used to describe all members of the family Bovidae that do not fall under the category of sheep, cattle, or goats. Usually, all species of the Alcelaphinae, Antilopinae, Hippotraginae, Reduncinae, Cephalophinae, many Bovinae, the grey rhebok, and the impala are called antelopes.
More species of antelope are native to Africa than to any other continent, almost exclusively in savannahs, with 20-35 species co-occurring over much of East Africa. Because savannah habitat in Africa has expanded and contracted five times over the last three million years, and the fossil record indicates this is when most extant species evolved, it is believed that isolation in refugia during contractions was a major driver of this diversification. Other species occur in Asia: the Arabian Peninsula is home to the Arabian oryx and Dorcas gazelle. India is home to the nilgai, chinkara, blackbuck, Tibetan antelope, and four-horned antelope, while Russia and Central Asia have the Tibetan antelope, and saiga.
No antelope species is native to Australasia or Antarctica, nor do any extant species occur in the Americas, though the nominate saiga subspecies occurred in North America during the Pleistocene. North America is currently home to the native pronghorn, which taxonomists do not consider a member of the antelope group, but which is locally referred to as such (e.g. Antelope Valley). In Europe, several extinct species occur in the fossil record, and the saiga was found widely during the Pleistocene but did not persist into the later Holocene, except in Russian Kalmykia and Astrakhan Oblast.
Many species of antelopes have been imported to other parts of the world, especially the United States, for exotic game hunting. With some species possessing spectacular leaping and evasive skills, individuals may escape. Texas in particular has many game ranches, as well as habitats and climates, that are very hospitable to African and Asian plains antelope species. Accordingly, wild populations of blackbuck antelope, gemsbok, and nilgai may be found in Texas.
Antelope live in a wide range of habitats. Numerically, most live in the African savannahs. However, many species are more secluded, such as the forest antelope, as well as the extreme cold-living saiga, the desert-adapted Arabian oryx, the rocky koppie-living klipspringer, and semiaquatic sitatunga.
Species living in forests, woodland, or bush tend to be sedentary, but many of the plains species undertake long migrations. These enable grass-eating species to follow the rains and thereby their food supply. The gnus and gazelles of East Africa perform some of the most impressive mass migratory circuits of all mammals.
Antelopes vary greatly in size. For example, a male common eland can measure 178 cm (70 in) at the shoulder and weigh almost 950 kg (2,090 lb), whereas an adult royal antelope may stand only 24 cm (9.4 in) at the shoulder and weigh a mere 1.5 kg (3.3 lb).
Not surprisingly for animals with long, slender yet powerful legs, many antelopes have long strides and can run fast. Some (e.g. klipspringer) are also adapted to inhabiting rock koppies and crags. Both dibatags and gerenuks habitually stand on their two hind legs to reach acaciaand other tree foliage. Different antelope have different body types, which can affect movement. Duikers are short, bush-dwelling antelope that can pick through dense foliage and dive into the shadows rapidly. Gazelles and springbok are known for their speed and leaping abilities. Even larger antelope, such as nilgai, elands, and kudus, are capable of jumping 2.4 m (7.9 ft) or greater, although their running speed is restricted by their greater mass.
Antelope have a wide variety of coverings, though most have a dense coat of short fur. In most species, the coat (pelage) is some variation of a brown colour (or several shades of brown), often with white or pale underbodies. Exceptions include the zebra-marked zebra duiker, the grey, black, and white Jentink’s duiker, and the black lechwe. Most of the “spiral-horned” antelopes have pale, vertical stripes on their backs. Many desert and semidesert species are particularly pale, some almost silvery or whitish (e.g. Arabian oryx); the beisa and southern oryxeshave gray and black pelages with vivid black-and-white faces. Common features of various gazelles are white rumps, which flash a warning to others when they run from danger, and dark stripes midbody (the latter feature is also shared by the springbok and beira). The springbok also has a pouch of white, brushlike hairs running along its back, which opens up when the animal senses danger, causing the dorsal hairs to stand on end.
Antelope are ruminants, so have well-developed molar teeth, which grind cud (food balls stored in the stomach) into a pulp for further digestion. They have no upper incisors, but rather a hard upper gum pad, against which their lower incisors bite to tear grass stems and leaves.
Like many other herbivores, antelopes rely on keen senses to avoid predators. Their eyes are placed on the sides of their heads, giving them a broad radius of vision with minimal binocular vision. Their horizontally elongated pupils also help in this respect. Acute senses of smell and hearing give antelope the ability to perceive danger at night out in the open (when predators are often on the prowl). These same senses play an important role in contact between individuals of the same species; markings on their heads, ears, legs, and rumps are used in such communication. Many species “flash” such markings, as well as their tails; vocal communications include loud barks, whistles, “moos”, and trumpeting; many species also use scent marking to define their territories or simply to maintain contact with their relatives and neighbors.
Many antelope are sexually dimorphic. In most species, both sexes have horns, but those of males tend to be larger. Males tend to be larger than the females, but exceptions in which the females tend to be heavier than the males include the bush duiker, dwarf antelope, Cape grysbok, and oribi, all rather small species. A number of species have hornless females (e.g. sitatunga, red lechwe, and suni). In some species, the males and females have differently coloured pelages (e.g. blackbuck and nyala).
The size and shape of antelope horns varies greatly. Those of the duikers and dwarf antelopes tend to be simple “spikes”, but differ in the angle to the head from backward curved and backward pointing (e.g. yellow-backed duiker) to straight and upright (e.g. steenbok). Other groups have twisted (e.g. common eland), spiral (e.g. greater kudu), “recurved” (e.g. the reedbucks), lyrate (e.g. impala), or long, curved (e.g. the oryxes) horns. Horns are not shed and their bony cores are covered with a thick, persistent sheath of horny material, both of which distinguish them from antlers.
Horns are efficient weapons, and tend to be better developed in those species where males fight over females (large herd antelope) than in solitary or lekking species. With male-male competition for mates, horns are clashed in combat. Males more commonly use their horns against each other than against another species. The boss of the horns is typically arranged in such a way that two antelope striking at each other’s horns cannot crack each other’s skulls, making a fight via horn more ritualized than dangerous. Many species have ridges in their horns for at least two-thirds the length of their horns, but these ridges are not a direct indicator of age.
Antelope pursue a number of defense strategies, often dictated by their morphology.
Large antelope that gather in large herds, such as wildebeest, rely on numbers and running speed for protection. In some species, adults will encircle the offspring, protecting them from predators when threatened. Many forest antelope rely on cryptic coloring and good hearing to avoid predators. Forest antelope often have very large ears and dark or striped colorations. Small antelope, especially duikers, evade predation by jumping into dense bush where the predator cannot pursue. Springboks use a behavior known as stotting to confuse predators.
Open grassland species have nowhere to hide from predators, so they tend to be fast runners. They are agile and have good endurance—these are advantages when pursued by sprint-dependent predators such as cheetahs, which are the fastest of land animals, but tire quickly. Reaction distances vary with predator species and behaviour. For example, gazelles may not flee from a lion until it is closer than 200 m (650 ft)—lions hunt as a pride or by surprise, usually by stalking; one that can be seen clearly is unlikely to attack. However, sprint-dependent cheetahs will cause gazelles to flee at a range of over 800 metres (1⁄2 mile).
About 25 species are rated by the IUCN as endangered, such as the dama gazelle and mountain nyala. A number of subspecies are also endangered, including the giant sable antelope and the mhorr gazelle. The main causes for concern for these species are habitat loss, competition with cattle for grazing, and trophy hunting.
The chiru or Tibetan antelope is hunted for its pelt, which is used in making shahtoosh wool, used in shawls. Since the fur can only be removed from dead animals, and each animal yields very little of the downy fur, several antelope must be killed to make a single shawl. This unsustainable demand has led to enormous declines in the chiru population.
The saiga is hunted for its horns, which are considered an aphrodisiac by some cultures. Only the males have horns, and have been so heavily hunted that some herds contain up to 800 females to one male. The species has shown a steep decline and is critically endangered.
It is difficult to determine how long antelope live in the wild. With the preference of predators towards old and infirm individuals, which can no longer sustain peak speeds, few wild prey-animals live as long as their biological potential. In captivity, wildebeest have lived beyond 20 years old, and impalas have reached their late teens.