It’s easy to tell Grant’s gazelles from other antelopes: They’re the ones wearing pants! Grant’s are one of the three larger gazelle species that compose the Nanger genus. Although all of them have white fur that extends up over the tail onto their backsides, creating the appearance of pants, this patterning is most dramatic in the Grant’s species. These gazelles are also remarkable for their ability to withstand extremely high body temperatures that would kill most other mammals.
Mammal
Diurnal/Nocturnal
Herbivorous
In captivity: 19 years
Lower risk
Male: 117.0 to 154.5 lb (53.2 to 70.1 kg)
Female: 11.0 to 101.2 lb (40.0 to 45.9 kg)
Male: 34 to 36 in (86.4 to 91.4 cm)
Female: 29.3 to 32.8 in (74.4 to 83.3 cm) high at shoulder
Tracks: Longer than a gerenuk's, with toes more widely splayed; twice the size of a Thomson's gazelle print
Scat: Rounded at one end, pointed at the other; used to mark territory boundaries
How can you tell the two subspecies of Grant’s gazelles apart?
The granti subspecies (most likely to be seen at Laikipia) has antlers that spiral inward, with the tips facing each other. The robertsi subspecies has horns that curve out and back.
The social structure of Grant’s gazelles depends on habitat and season. On the plains of the Serengeti, Grant’s live mostly in mixed herds of males and females, numbering up to 400. As a herd moves throughout its home range, it occasionally enters a region belonging to a territorial male who becomes dominant over the herd’s males and takes charge of the females. In woodland areas, mixed groups are much less common. In this habitat, Grant’s tend to form groups of females with a single male, while other males live on their own. Woodland herds do not have more than 40 individuals. The number of mixed herds increases during the dry season, when there is little territoriality. During the wet season, territoriality increases, and herds tend to split into smaller groupings, the largest of which are the breeding herds. No matter the habitat, Grant’s gazelle herds are loosely composed; individuals join and leave with ease, especially during migration. The only exception is a harem group, made up of about 10 to 25 females and a territorial male. These herds are “half-open,” meaning that females can easily join but have a harder time leaving the male’s area.
Most communication between Grant’s gazelles is visual. Smell also factors into communication, as territorial males use scent to mark their territories. Grant’s gazelles also emit noises during courtship and to send up an alarm.
Though they are often found near each other, the Grant’s gazelle and the Thomson’s gazelle belong to different genera and have remarkably distinct territorial behavior. A territorial male Grant’s gazelle tears up grass with his horns and marks the boundary of his area with urine. In contrast, a territorial male Thomson’s gazelle marks his boundary with secretions from glands near his eyes. A territorial Grant’s male is easier to spot, as he stands in plain view to publicize his status. While Thomson’s territorial males engage in fights along their borders, their Grant’s counterparts simply keep a constant eye on neighboring activities.
Poaching and competition with livestock are the biggest threats to Grant’s gazelle populations. Of the three species within the Nanger genus, Grant’s are fairly stable, as a high percentage of these gazelles resides within protected regions, such as the Serengeti and the Maasai Mara.
Nanger gazelles range from northeastern Uganda to Somalia, and from Ethiopia and Sudan down to central Tanzania. Most are in Kenya and Tanzania.
Although Nanger gazelles live in habitats ranging from savanna to semi-desert, the Grant’s gazelle prefers open plains as well as cooler, elevated uplands. These gazelles eat longer grass than most other gazelle species do, and they prefer habitats with hard soil—two factors that make the Serengeti their ideal habitat.
Most other Nanger gazelles are primarily browsers, but Grant’s eat both trees and grass depending on the season. Though they prefer shrubs and herbs, they shift to tall grass during the dry season and occasionally eat fruit. Because Grant’s gazelles do not rely on water, they are remarkably well adapted to living in dry and arid regions. In fact, Grant’s gazelles can live their entire lives without taking a drink.
Female Grant’s gazelles begin to mate when they are one-and-a-half years old, while males become sexually mature at age three. When a female Grant’s gazelle is ready to mate, she signals her readiness by holding her tail straight and horizontal. The male then begins an elaborate courtship. With his tail up and his nose in the air, the male follows the female and performs a “goosestep,” a stiff-legged kicking action similar to that of the Thomson’s gazelle. If the female declines to mate, the male generally lets her go. If she is receptive, she walks slowly and swings her head about while the male mounts her. (Walking while mating is characteristic of gazelle breeding.) Females have a gestation period of about 198 or 199 days and give birth to a single calf, usually either between December and February or between August and September. A newborn gazelle enters a “lie-down period,” when it remains completely concealed. When the mother returns to feed her fawn, she calls it by bleating or bobbing her head. The fawn runs to her, and they touch noses. After about four to six weeks, the young can follow its mother and other offspring in peer groups. The bond between mother and fawn remains strong until it reaches adolescence.
The Grant’s gazelle’s ability to survive without water gives it a solid safety net, since avoiding water holes means avoiding large predators. Lions, African wild dogs, cheetahs, and others prefer the smaller Thomson’s gazelle to the Grant’s. The Grant’s gazelle’s biggest threat is the black-backed jackal, a rather small predator. By hunting in pairs, jackals can overcome a mother gazelle and prey upon her young.
Kenya, which has an estimated population of 100,000 Nanger gazelles, has the largest population of these antelopes. Although this figure reflects a 50 percent decrease since the 1960s, these gazelles still range widely in both protected and unprotected regions. The total population of Grant’s gazelles throughout its range is estimated at more than 75,000.
Grant’s gazelles migrate backward! Thomson’s gazelles, wildebeest, and zebras move away from dry regions in search of water; Grant’s gazelles move into these areas, where their ability to live without water means less competition for food.
