Antelope

Antelope are herbivorous mammals of the family Bovidae, often noted for their horns. These animals are spread relatively evenly throughout the various subfamilies of the Bovidae and many are more closely related to cows or goats than to each other. There are many species of antelope, ranging in size from the tiny Royal Antelope to the elands. They typically have a light and elegant frame, slender, graceful limbs, small cloven hoofs, and a short tail. Antelope have powerful hindquarters and, when startled, they run with a peculiar bounding stride that makes them look as though they are bouncing over the terrain like giant rabbits.

There are about 90 antelope species of antelope in about 30 genera, of which about 15 are endangered. These include:

• addax
• bluebuck
• bongo
• bontebok
• common eland
• dik-dik
• duiker
• gazelle
• gerenuk
• gemsbok
• hartebeest
• impala
• klipspringer
• kudu
• nyala
• oribi
• oryx
• grey rhebok
• roan antelope
• royal antelope
• sable antelope
• springbok
• suni
• Tibetan antelope
• topi
• waterbuck
• wildebeest

Black Buck Antelope have been imported into the United States, primarily for the purpose of "exotic game hunts", common in Texas. There are no true antelope native to the Americas. The Pronghorn "Antelope" of the Great Plains belongs to family Antilocapridae. The Mongolian Gazelle (Procapra gutturosa), sometimes classified as an antelope, can run with a speed of 80 km/h (50 mph). Suni are small antelope that live in south-eastern Africa. They stand 12–17 inches high at the shoulder. They are very similar to the dik-dik in size, shape, and color but have many smaller differences.

Antelope are not a cladistic group in and of themselves, but rather are a sort of miscellaneous group. The term is used loosely to describe all members of the family Bovidae which do not fall under the category of sheep, cattle, or goat. Native antelope can be found in Eurasia and Africa.

There are at least two classification systems at the subfamily level of the Bovidae. In the "lumped" system (of, e.g., Kingdon 1997), antelope occur in both subfamilies—the Bovinae (alongside the cattle) and the Antilopinae (alongside the sheep and goats). The alternative classification of 10 subfamilies is given under "Bovid" in this encyclopaedia—in this classification, antelope occur in 9 of the 10 subfamilies (one of which is the single-species subfamily of the Tibetan Antelope).

Antelopes occur naturally in Eurasia and Africa. Although there are native cattle, goats and sheep (and the non-bovid Pronghorn) in North America, antelopes themselves are absent from the Americas (although Blackbuck and Gemsbok have been introduced onto ranches in the USA).

The characteristics of bovids in general are: long legs; even number of hoofed toes (as per all even-toed ungulates); in most species the males are horned, and in some species the females are also; most have horizontally oriented pupils; they ruminate.

These basic characteristics, however, mask huge differences in appearance between antelopes, cattle, goats and sheep, and among the antelopes themselves. For example, a male Common Eland can measure 178 cm at the shoulder and weigh almost 950 kg, whereas an adult Royal Antelope may stand only 24 cm at the shoulder and weigh a mere 1.5 kg.

Not surprisingly for animals with long slender yet powerful legs, antelopes have long strides and can run fast. They can jump well, but few (e.g. Klipspringer) are adapted to climbing. Both Dibatags and Gerenuks habitually stand on their hind legs to reach acacia and other tree foliage.

Antelopes have a dense coat of short fur. In most species, the coat (pelage) is some variation of a brown color (or several shades of brown); often with white or pale under-bodies. 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 sub-desert species are particularly pale, some almost silvery or whitish (e.g. Arabian Oryx); the Beisa and Southern Oryxes have gray and black pelage with vivid black-and-white faces. Common features of various gazelles are a white rump, which flashes a warning to others when they run from danger, and a dark stripe mid-body (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.

Antelopes are ruminants, and thus 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. The fact that most species have their pupils elongated horizontally also helps 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 head, 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.

In most species, both sexes have horns—but those of males tend to be larger. Size and shape of horns varies immensely. 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 efficient weapons and tend to be better developed in those species where males genuinely fight over females—horns are clashed in combat.

There is a tendency for males to be larger than the females; however, 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 different coloured pelage (e.g. Blackbuck and Nyala).

It is difficult to determine how long antelope live in the wild. In captivity, wildebeest have lived beyond 20 years old, and Impalas have reached their late teens. In the wild, few individuals of prey species live to old age, as the old and weak fall easier prey to their predators; antelopes are no exception to this rule.

With food that does not move, antelopes (like other herbivors) do not need any great intelligence. However, they do need to be able to react quickly in the presence of a predator—thus, they tend to be fast runners. They are agile (able to execute fast turns on the run) and have good endurance (ability to keep running for some time)—these are advantages when pursued by sprint-dependent predators like cheetah, which are the fastest of land animals, but tire quickly.

Different species differ in their behavior in the presence of predators, and these differences are often associated with habitat. For example, the Steenbok of open woodland will lie low until the last minute and then bound away. Plains-living species, such as gazelles, do not have this choice and must flee at speed when a predator approaches. Reaction distances vary with predator species and predator behavior. 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 over 800 m (0.5 mile).

Species of forest, woodland or bush tend to be sedentary, but many of the plains species undertake huge migrations. These migrations enable grass-eating species to follow the rains and therefore their food supply. The gnus and gazelles of East Africa perform some of the most impressive mass migratory circuits of all mammals.