Gazelles
Gazelles
Territory and social arrangements
Gazelles are medium-sized fawn-colored antelopes found in arid parts of the world, mainly in Ethiopia, Somalia, northern Africa and around the Sahara Desert, parts of the Middle East, India, and Central Asia. Gazelles are horned animals with a four-chambered stomach and cloven hooves. They are cud chewers (ruminants), and lack upper canine and incisor teeth. Gazelles tear grass, foliage, buds, and shoots with a sideways motion of their jaws, superficially chewing and swallowing this forage. The food is acted on by bacteria in the S-shaped rumen section of the stomach, then regurgitated and chewed again.
Gazelles are grayish brown with white underbellies and rumps. They have conspicuous black and white facial markings and a horizontal dark-colored band along their flanks. Gazelles have slender bodies, long necks, S-shaped, ringed horns, and long legs. Their vision and hearing are well-developed. Gazelles have a distinctive way of walking, called stotting, a stiff-legged bouncing motion where all four legs hit the ground at the same time. Gazelles can be seen performing this unusual movement in moments of playfulness or when they are frightened. They have a 10-12 year life span.
Territory and social arrangements
Gazelle social arrangements vary according to the terrain they inhabit. Where food sources are abundant they are found in large herds, but in desert regions their populations are lower. In the savanna areas of Africa, Thomson gazelles are found in large numbers. The size of the territory ranges from 38-150 acres (15-61 hectares; Grant’s gazelle, East Africa), to 250-550 acres (101-223 hectares; Edmi gazelles, Middle East), to 325-850 acres, (132-344 hectares; gerenuk or giraffe gazelle, East Africa).
Males establish territories during the mating season and routinely exclude other males. Harem herds of female gazelles with dependent young, are defended by one dominant male. Maternal herds, without a male present in the territory, and bachelor herds of male gazelles are also found. At times there are large mixed herds without a territorial male present, seen during periods of migration.
Gazelles mark their territories in much the same way as other ruminants do. They deposit dung heaps around the territory and they mark bushes with their scent glands. Glands can be found under the eyes (preorbital glands), on the hooves, shins, back and around the genital area depending on the particular species. When another male enters a territorial male’s domain, there is no fighting as long as the intruder displays subordinate behavior. A subordinate male will keep his head low with his chin out and will not approach the females of the herd.
One of the smallest species is the Dorcas gazelle (Gazella dorcas ) of North Africa (Algeria to Egypt) and Sudan, which is less than 2 ft (0.61 m) at the shoulder. The common gazelles of East Africa include Thomson’s gazelle (G. thomsonii ), with black flanks and erect horns, and Grant’s gazelle (G. granti ) which is up to 3 ft (0.915 m) at the shoulder, and the largest of all gazelles. The red-fronted gazelle (G. rufifrons ) is found from Senegal to the Sudan.
Males within an all-male herd will frequently display intimidation behavior toward one another, but these do not often lead to attacks or injuries. Bucks will push their foreheads against one another in a display of intimidation. This may lead to interlocking horns, but they usually disengage before any serious damage occurs. Bucks will sometimes stand parallel to one another, head to rump, and walk around each other in circles. They may also engage in a chin-up display where they stretch their necks and bend them backwards towards one another. Within the male herds this behavior establishes dominant and submissive roles.
Mating and breeding
The mating ceremony among gazelles is ritualized. The male lowers and stretches his head and neck, following the female closely in a marchlike walk, lifting his head, and prancing. The lifting of a foreleg during the mating march is also characteristic and vocal noises are made by the male. The female responds to the male’s low stretch by urinating. She may walk away, circle, and make sharp turns. When she is ready for mating, she will display submissive behavior by holding her tail out.
Gestation (pregnancy) lasts around six months for gazelles. During birthing, the mother alternates between standing and lying down. Twenty minutes after birth a Grant’s gazelle has been seen to stand up and be nursed by its mother. In its early days a fawn (newborn) divides its time between feeding and hiding out in the grass. Typically fawns lie in a different hiding place after each feeding. The mother will keep watch over the newborn from a distance. Many gazelles reproduce twice a year when sufficient food supplies are available.
Conservation and adaptation
In parts of Africa where national wildlife parks have been established, gazelles can be found in large numbers. In some parts of North Africa, Arabia, and the Near East, however, where they have not had protection, many species of gazelle have been nearly wiped out. Some gazelles that were close to extinction have been saved through the efforts of particular governments or by individuals in cooperation with zoos.
A number of species of gazelle survive well in arid desert regions. Notable among them is the gerenuk
KEY TERMS
Bachelor herds —A group of young, nonterritorial males.
Intimidation —Threatening behavior among the same sex for the purpose of expressing dominance or for preventing intruders from entering the territory.
Maternal herd —A group of females with their dependent young.
Ruminant —A cud-chewing animal with a four-chambered stomach and even-toed hooves.
Stotting —A bounding movement where the animal will bounce and land on all four legs in response to threatening situations.
Territorial male —A male that defends its area and harem from other males.
(Litocranius walleri ), or giraffe gazelle, so called for the habit of standing up to forage for food. The gerenuk is able to balance itself on its rear legs and it has an unusually long neck. In zoos, this gazelle seems never to drink water and has only on rare occasions been seen to drink in its natural habitat.
Resources
BOOKS
Estes, Richard D. Behavior Guide to African Mammals. Berkeley: University of California, 1991.
Haltenorth, T. and Diller, H. A Field Guide to the Mammals of Africa. London: Collins, 1992.
Nowak, Ronald M. Walker’s Mammals of the World. 6th ed. Baltimore: The Johns Hopkins University Press, 1999.
Spinage, C.A. The Natural History of Antelopes. New York: Facts on File, 1986.
Walther, Fritz R., Elizabeth C. Mungall, and Gerald A. Grau. Gazelles and Their Relatives: A Study in Territorial Behavior. Park Ridge, NJ, Noyes Publications, 1983.
Vita Richman