While many predators are threats to N. granti, cheetahs (Acinonyx jubatus), wild dogs (Lycaon pictus), and golden jackals (Canis aureus) are particularly fond of N. granti fawns. During the rainy season, when the ground is soft, cheetahs (Acinonyx jubatus) take advantage of the greatly reduced speed of these gazelles.
Nanger granti uses anti-predatory signals including alert posture and alert snorts. They avoid areas with a high density of predators and employ cooperative defense to protect vulnerable fawns.
Known Predators:
Grant's gazelles are large, pale gazelles with long horns and legs. They have a distinct rectangular, white shape on the hindquarters and a contrasting black stripe running down the thigh. Thomson’s gazelles (Eudorcas thomsonii), a closely related species, have some similar physical characteristics. They both possess white coloring on the hindquarters, but Grant’s gazelles have more white than Thompson’s gazelles. Nanger granti is paler and has bigger horns than Thompson's gazelles.
Males and females are dimorphic. Males are larger than females, and they have longer, thicker horns, ranging from 50 to 80 cm. The horns are ringed. In contrast to males, females have smaller horns (30 to 40 cm) that are thin and symmetrical.
The young are more darkly colored than adults.
Range mass: 45 to 65 kg.
Range length: 140 to 166 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger; ornamentation
Grant's gazelles have an average lifespan of around 12 years.
Average lifespan
Status: wild: 12 years.
Average lifespan
Status: wild: 12 years.
Grant’s gazelle habitat consists of semi-desert, open savannas, and treeless plains. They avoid acacia forests unless they are traversed by well-traveled paths.
Range elevation: 2500 (high) m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: desert or dune ; savanna or grassland
A Ugandan tribe uses Grant’s gazelles as one of their four major totems. They are also respected as animals possessing great beauty.
Grant's gazelles communicate through territorial markings made with urine and feces, sex pheromones, and visual displays. They communicate the presence of a predator by alert posture, alarm snorts, and stamping.
The dark coloration around the female’s anus serves as source of visual attraction between a fawn and its mother.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: pheromones ; scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
According to the IUCN, a threat to N. granti is human habitat destruction. Habitat loss is leading to population decreases of Grant's gazelles.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
There seems to be no negative impacts caused by N. granti.
The inadvertent control of the pouched mice (Saccostomus campestris) populations by N. granti is advantageous to humans. In addition to being agricultural pests, pouched mice may spread disease. Grant's gazelles are sometimes hunted for meat and trophies and they are sought by ecotourists.
Positive Impacts: food ; body parts are source of valuable material; ecotourism ; controls pest population
Grant’s gazelles are prey for cheetahs (Acinonyx jubatus), wild dogs (Lycaon pictus), and golden jackals (Canis aureus). They are also important herbivores in the habitats in which they live.
Nanger granti inadvertently affects the population density of pouched mice (Saccostomus mearnsi) in eastern Africa by depleting the supply of food for these rodents. In areas where Grant’s gazelles are less common, S. mearnsi populations flourish.
Ecosystem Impact: disperses seeds; creates habitat
Nanger granti are primarily browsers, rather than grazers. A large part of their diet consists of leaves and stems.
Since N. granti live in an arid environment, water conservation and consumption is important for survival. While Thomson’s gazelles uses evaporative cooling as a method of decreasing body temperature, Grant's gazelles allow their body temperature to rise with air temperature, dissipating body heat to the surrounding air when temperatures fall. At night they may also eat leaves, which contain more water during the cooler, nighttime hours.
Plant Foods: leaves; wood, bark, or stems
Primary Diet: herbivore (Folivore )
Nanger granti is found only in eastern Africa, where they range up to 2,000 meters in altitude.
Grant’s gazelles migrate seasonally over a large part of their range preferring higher, well-drained areas during the rainy season, and moving to lower, grassy valleys during the dry season. They are not dependent on water and, consequently, they migrate in the opposite direction of water-dependent species such as Thomson’s gazelles, wildebeest, zebras, and topi. In doing so, Grant’s gazelles avoid competition and are able to survive on vegetation found in this semi-desert environment. However, N. granti remain throughout the year in areas where there is a plentiful supply of food.
Biogeographic Regions: ethiopian (Native )
When a female gazelle is in estrus, her urine contains sex pheromones indicating her reproductive status to males. In order to detect these, males perform flehmen behavior. Males curl their lips and suck air into their vomeronasal organs to detect whether sex pheromones are present. This behavior is done by N. granti as well as G. thomsonii.
If pheromones are detected, the male actively pursues the female. Courting takes place, in which the male prances with his head held high and his tail held horizontally. This eventually leads to copulation. However, if no sex pheromones are detected, the male does not further pursue the female.
Mating System: polygynous
Grant's gazelles reach sexual maturity at three years of age for males and about one and half years for females. Timing of the mating season depends on location. For example, in southern Kenya and Tanzania, mating takes place throughout the year. In the Serengeti, mating takes place in all months except June, July, October, and November. The gestation period is about 27 weeks.
Breeding interval: Females typically give birth once per year.
Breeding season: Gran't gazelles can breed throughout the year but local climate affects the timing of reproduction.
Range number of offspring: 1 (low) .
Average number of offspring: 1.
Range gestation period: 6 to 6.63 months.
Average gestation period: 6.3 months.
Average weaning age: 6 months.
Average time to independence: 1.5 years.
Average age at sexual or reproductive maturity (female): 1.5 years.
Average age at sexual or reproductive maturity (male): 3 years.
Key Reproductive Features: seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; induced ovulation ; viviparous
After birth, the fawn is completely cleaned of any fluids by the mother. The fawn then drinks its first meal of milk and seeks protection near its mother. If the mother is going out to graze, the fawn remains in a secure hiding place which is observable to the mother from where she is grazing. The mother-fawn relationship is the only persistent relationship in N. granti.
Parental Investment: altricial ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female); post-independence association with parents
Grant's gazelle (Nanger granti) is a relatively large species of gazelle antelope, distributed from northern Tanzania to South Sudan and Ethiopia, and from the Kenyan coast to Lake Victoria.[3] Its Swahili name is swala granti.[4] It was named for a 19th-century British explorer, James Grant.[5]
Grant's gazelle is genetically related to Soemmerring's gazelle (N. soemmerringii) and Thomson's gazelle (Eudorcas thomsonii) with Soemmering's gazelle being the closer relative.[3] Grant's gazelle shows high genetic variation among its populations, although 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.[3] Grant's gazelle was formerly considered a member of the genus Gazella within the subgenus Nanger before Nanger was elevated to genus status. In 2021, the American Society of Mammalogists granted full species status to Bright's gazelle (Nanger notatus) and the Peter's gazelle (Nanger petersii).[6][7]
Listed alphabetically.[2]
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).[8][4] 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. A useful field mark is the white on the rump that extends over the top of the tail in Grant's but not Thomson's gazelles. The subspecies are segregated by different morphological characters, such as horn shape and slight differences in coat colour.[3] These differences are not indicative of ecological separation as with some species.[3]
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,[3] relying on more browse or leafy material during dry seasons to supplement their intake of water.[9] They are sometimes migratory, but do not travel along with 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 less competition.
The most common predators of the Grant's gazelle are cheetahs[10] and wild dogs. Humans also 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.[10] Jackals are major predators of fawns.
The Grant's gazelle is a gregarious, territorial, and sometimes migratory species.[3] The home ranges of females overlap with those of the males. 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 female that tries to leave is aggressively herded back.[11] Most of the time, the male's stance in relation to her is enough to keep the female from leaving.
Bachelor groups are made up of adolescent and adults not holding territory. Any new members perform intimidation displays to enter the group.[12] However, bachelor groups tend to be loose and members can leave whenever they want. Grant's gazelles will sometimes join groups of Thomson's gazelles to protect themselves from predators. Predators are less likely to attack the Grant's gazelle when associated with these mixed groups, perhaps because the Thomson's gazelle provides an easier target.[13] The larger, older males with thick horns have the best chance of establishing a territory.[14] 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.[15] 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 males more often than older ones. Dominant males can simply run off subordinates rather than having to display to them.
Grant's gazelles are generally mixed feeders that both browse and graze. In one study, their diet consisted of 66% browse and 34% graze.[16] Rainfall seems to be a determinant of their diets.[16] One way the Grant's gazelle withstands dehydration and heat stress is by being very efficient in digesting dry matter. Grant's gazelles consume a smaller amount of food than domesticated animals, but they are better-suited for extreme environments because they derive protein from forage more quickly.[17] The Grant's gazelle's diet may be responsible for the slow growth rates of browsed plants.[18] They get most of their moisture from the plants they eat, so they do not often have to drink water. Thus they can stay on the plains long after the rains end. In dry seasons, gazelles move deep into dense brush and wait for the next rains.[12] They will eat red oat grass and small, tough plants,[19] which are avoided by the other ungulates. This allows the gazelles to survive in the brush during the dry season. Grant's gazelles eat mainly dicotyledons during the dry season and grass in the wet season.[20]
Grant's gazelles sexually mature at 18 months. Territory-holding males mate more than those in bachelor groups.[15] The courting ritual begins with a male following a female, waiting for her to urinate. When she does, the male does the Flehmen response to determine if she is in estrus.[21] If she is, he will continue to follow her. The female will lift her tail, signaling she is ready to mate, and the male will mount her.[15] The gestation period for the gazelle lasts for 198 days.[22] Births in the Serengeti peak in January and February. A female will leave her herd and find a well-hidden place to give birth. Afterwards, the female eats the afterbirth and other fluids to keep the fawn clean and scentless. Females that have recently given birth will stay together for protection.[15] The females nurse their fawns four times a day. Fawns are immobile for the first few days, and the mother stays close by.[23] When the fawn can walk, it leaves with its mother to join a herd.[24] Around this time, fawns will associate with one another in peer groups. A gazelle is weaned at six months, but will continue to associate with its mother until adolescence.[15]
The Grant's gazelle is still a common species, despite having been eradicated in certain areas. Major threats have been habitat destruction and poaching. The gazelle's status as an unthreatened species is dependent on protection of the national parks and reserves where it lives, including Serengeti National Park and Ngorongoro Conservation Area in Tanzania, and Lake Turkana National Parks in Kenya. Estimates of the population range from 140,000 to 350,000. While certain areas have stable populations, overall the population trend is going downward.[1]
{{cite web}}: CS1 maint: archived copy as title (link) Grant's gazelle (Nanger granti) is a relatively large species of gazelle antelope, 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 British explorer, James Grant.
