Grant's gazelle

The Grant's gazelle (Nanger granti, syn. Gazella granti) is a species of gazelle distributed from northern Tanzania to South Sudan and Ethiopia, and from the Kenyan coast to Lake Victoria. Its Swahili name is swala granti. It was named for a 19th-century Scottish explorer, Lt Col Grant. Grant's gazelle is more genetically related to Soemmerring's gazelle (N. soemmerringii) and Thomson's gazelle (Eudorcas thomsonii) with Soemmering's gazelle being the closest relative of the two species. Grant's gazelle shows high genetic variation among its populations, though there is no geographic isolation. The differentiation of the species may have evolved during repeated expansion and contraction of arid habitats during the late Pleistocene era in which populations were possibly isolated. Grant's gazelle was formerly considered a member of the genus Gazella within the subgenus Nanger before Nanger was elevated to genus status. Listed alphabetically. The Grant's gazelle stands 75–95 cm (30–37 in) at the shoulder. The females weigh from 35 to 50 kg (77 to 110 lb) and males from 50 to 80 kg (110 to 180 lb). Its coat is a beige orange on the back with a white belly. The Grant's gazelle looks similar to a Thomson's gazelle, except it is much larger and has lyre-shaped horns which are stout at the base, clearly ringed, and measuring 45–81 cm (18–32 in) long. The subspecies are segregated by different morphological characters, such as horn shape and slight differences in coat colour. These differences are not indicative of ecological separation as with some species. The Grant's gazelle is found in East Africa and lives in open grass plains and is frequently found in shrublands; it avoids areas with high grass where the visibility of predators is compromised. They also occur in semiarid areas and are relatively well adapted to dry areas, relying on more browse or leafy material during dry seasons to supplement their intake of water. They are migratory animals, but travel in the opposite direction of most of the other ungulates, such as Thomson's gazelles, zebras, and wildebeest, which are more water dependent. They can subsist on vegetation in waterless, semiarid areas, where they face little competition. The most common predators of the Grant's gazelle are cheetahs and wild dogs. Humans also tend to hunt gazelles. In the Serengeti, Grant's gazelle is a prey item for cheetahs, but the Thomson's gazelle is preferred. However, in Nairobi National Park, Grant's gazelle is preferred over Thomson's gazelle, making it an important resource to the cheetah. Jackals are major predators of fawns. The Grant's gazelle is a gregarious, territorial, and migratory species. The home ranges of does overlap with those of the bucks. Only male gazelles are territorial. Male gazelles will herd all females that cross their territories. When the females are in estrus, they are strongly guarded by the dominant male, which prevents other males from mating with them. Any doe that tries to leave is aggressively herded back. Most of the time, the buck's simple stance in relation to her is enough to keep the female from leaving. Bachelor groups are made up of adolescent and bucks not holding territory. Any new members must perform intimidation displays to enter the group. However, bachelor groups tend to be very loose and members can leave whenever they want. The larger, older males with thick horns have the best chance of establishing a territory. Conflicts between adult males are usually solved with intimidation displays. The bucks circle each other and swing their necks from side to side, displaying their neck power. Neck strength is important in an actual fight and the male that cannot keep up yields. Gazelles of nearly equal neck strength are more likely to engage in actual combat. Fighting occurs in young bucks more often than older ones. Dominant bucks can simply run off subordinates rather than having to display to them.