Gazella dorcas
TAXONOMY
Capra dorcas (Linnaeus, 1758), lower Egypt.
OTHER COMMON NAMES
French: Gazelle dorcas.
PHYSICAL CHARACTERISTICS
Dorcas gazelles have a head and body length of 3.0–3.6 ft (90–110 cm), tail length of 6–8 in (15–20 cm), shoulder height of 1.8–2.1 ft (55–65 cm), and weight of 27–44 lb (12–20 kg). They are considered one of the smallest of the gazelles, but proportionately are the longest limbed. Their slender limbs contain splayed hooves. They can reach running speeds of 60 mph (95 kph) and can maintain steady speeds of 30 mph (48 kph). Dorcas gazelles have long ears. Across their nose is a fold of skin that can be inflated and vibrated when they feel threatened, thus generating a sound like the quacking of a duck. The upper coat is colored pale beige or sandy-red, while the undersides and rump are white. A wide, sometimes indistinct, rufous stripe runs along the lower flank between the front and rear legs; the stripe separates the white belly from the upper coat. Another similarly colored strip is located on the upper hind legs, creating a border for the white rump. The head is the same beige color as the body. There is a white ring around each eye, and a pair of white and dark brown streaks running from each eye to the corners of the mouth. The forehead and bridge of the nose are generally light reddish tan in color.
Strongly ridged, lyre-shaped (pointed outward and then coming in at the tips) horns are found in both sexes, but those of the females are smaller and more slender. They may have up to 25 annular rings on their horns. In males they are bent sharply backwards, and curve upwards at the tips, growing
10.0–15.2 in (25–38 cm) long. The horns of the females are much thinner and straighter, with fewer ridges, and a length of 6–10 in (15–25 cm).
DISTRIBUTION
Morocco south to Mauritania (and formerly to Senegal) east to southern Israel and Egypt and from there south to Sudan, northeastern Ethiopia, and northern Somalia.
HABITAT
They live in savannas, dry hills, sub-deserts, and true deserts; but prefer stony deserts to rocky deserts and avoid steep terrain. They live primarily on the perimeter of the Sahara, but it is not uncommon for them to venture further into the desert.
BEHAVIOR
Dorcas gazelles are well suited to desert climates. They may go their entire lives without drinking water, obtaining necessary moisture from plants that they eat. Being well adapted to dry climates, they produce very concentrated urine during dry weather. They are usually active, especially during hot weather, only at dawn, dusk, and throughout the night. However, they can withstand very hot temperatures, if necessary. Animals will migrate and run in herds over large areas in search for food. Herds tend to consist either of single-sex animals with up to 40 animals or mixed herds of up to 100. When not foraging for food, groups usually only reach about 12 in number, with one adult male. In order to defend against predators, groups of 2–5 males sometimes form. They tend to congregate in areas where recent rainfall has stimulated plant growth, and may also associate with other gazelles and camels.
Adult males are territorial, establishing piles of dung throughout their range in a conspicuous display in which the male will first paw at the ground, then stretch over the scraped area and urinate, and finally crouch with his anus just above the ground, at which time he deposits his dung. Males defend small territories during the breeding season or, sometimes when times are good, for the entire year. The preorbital glands, although functional, are not used for marking. Its call of alarm when sensing danger, which sounds like a duck's quack, is made through the nose, which inflates during the process.
FEEDING ECOLOGY AND DIET
Dorcas gazelles eat grasses, shoots, leaves (especially the pods of acacia trees), blossoms, and succulents. They also browse the green leaves of some bushes and dig up bulbs of perennial plants. Often they will stand on their hind legs to reach leaves high off the ground. They will occasionally eat invertebrates.
REPRODUCTIVE BIOLOGY
Polygamous. Mating season is December to November in the wild. In areas where agriculture (or nature) has led to below normal amounts of available water, they may breed at other times of the year. Female gestation period is 164–174 days, with usually one baby born (on rare occasions two are born). Newborns weigh 2.2–4.0 lb (1.0–1.8 kg). After birthing, mothers will hide their young for 2–6 weeks. Mothers will induce defecation in nursing young and ingest the feces (which is thought to be a water conservation adaptation). They are weaned after 2–3 months; become sexually mature at 9–12 months for females and at 18 months for males; and have a life span of up to 12.5 years in the wild and up to 17 years in captivity.
CONSERVATION STATUS
Vulnerable. According to IUCN, their population trends are drastically declining primarily due to overhunting. Predators include the common jackal, cheetah, lion, leopard, serval cat, desert lynx, wolf, striped hyena, vulture, and eagle. Smaller cats, honey badgers, jackals, and foxes eat fawns. They are particularly vulnerable when they migrate in large numbers.
SIGNIFICANCE TO HUMANS
They are hunted for their meat and skins. They help to keep vegetation from becoming overgrown.
