Thomson's Gazelle
Encyclopedia
The Thomson's gazelle is one of the best-known gazelle
s. It is named after explorer Joseph Thomson
and, as a result, is sometimes referred to as a "tommie". It is considered by some to be a subspecies of the Red-fronted Gazelle
and was formerly considered a member of the genus Gazella within the subgenus Eudorcas, before Eudorcas was elevated to genus status. Thomson's gazelles can be found in numbers exceeding 500 000 in Africa and are recognized as the most common type of gazelle in East Africa.
s as Thomson's gazelles. Although some Grant's do have the black stripe running across their sides, the white on their rump always extends above the tail.
region of Kenya
and Tanzania
. It has narrow habitat preferences being confined to short grassland with dry firm footing. It does, however, move into tall grassland and dense woodland during migration. Gazelles are mixed feeders. In the wet seasons, gazelles eat primarily lush green grasses, but during the dry seasons it starts to eat more browse particularly foliage, bushes, forbs, and clovers.
Thomson's gazelles are dependant on short grass. Their numbers highly concentrated at the beginning of the rains since the grass grows quickly. They follow the larger herbivores like plains zebra
s and blue wildebeest
s as they mow down the tall grasses. At this time the gazelles spread out more. In the wild, Thomson's gazelles can live up to 10–15 years. Their major predators are cheetah
s, which are able to attain higher speeds, but gazelles can outlast them in long chases and are able to make turns more speedily. This small antelope-gazelle can run very fast, up to 70 kph (43 mph), and zigzag, a peculiarity which often saves it from predators. They are also preyed on by lion
s, leopard
s, hyena
s, baboon
s, and crocodile
s. A noticeable behaviour of Thomson's gazelles is their bounding leap, known as stotting
or pronking, used to startle predators and display strength.
When patrolling his territory, a male may gore the grass, soil, or a bush with his horns. Males will also mark grass stems with a pre-orbital glands which emit a dark secretion. Territories of different males may share a boundary. When territorial males meet at the border of their territories they engage in mock fights in which they rush towards each other as if they are about to clash but they don’t touch. After this, they graze in a frontal position, then in parallel and them in reserve and move away from each other while constantly grazing. These rituals have no "winner" but merely "ratify" the position of the boundaries between the territories. Territorial males usually will not enter another males territory. If a male is chasing an escaping female he will stop the chase if she runs into another territory but the neighboring male will continue the chase.
. In the first six hours of the fawn’s life, it moves and rests with its mother but eventually turns away from its mother and lies down and hides in the grass. The mother stays in the vicinity of the fawn and returns to nurse it daily. Mother and fawn may spend an hour together walking and such before the fawn goes and lies back down to wait for the next nursing. Mother gazelles may associate with other gazelle mothers. However, the fawns do not gather into "kindergartens". Mother gazelles will defend their young against predators like jackals and baboons but not against larger predators. Sometimes, a female tommie can fend a male baboon off by headbutting him with her horns in order to defend her fawn.
As the fawn approaches two months old it spends less time lying out and more time with its mother. Eventually the lying out ends. Around this time the fawn starts eating solid food but continues to seek suckles from its mother. The pair will also join a herd. Young female gazelles may associate with their mothers for as yearlings. Young males may also follow their mothers, however as they reach adolescence they are noticed by territorial males and thus cannot follow their mothers into territories. The mother may follow and stay with him but eventually stops following him when he is driven away and the male will them join a bachelor group.
, Masai Mara
and Ngorongoro. Thomson's Gazelle occur in a number of protected areas in their range. The core areas of the Serengeti-Mara population are protected by the Serengeti N.P. and Masai Mara N.R., where the only land use allowed is wildlife tourism.
Gazelle
A gazelle is any of many antelope species in the genus Gazella, or formerly considered to belong to it. Six species are included in two genera, Eudorcas and Nanger, which were formerly considered subgenera...
s. It is named after explorer Joseph Thomson
Joseph Thomson (explorer)
Joseph Thomson was a Scottish geologist and explorer who played an important part in the Scramble for Africa. Thomson's Gazelle is named for him. Excelling as an explorer rather than an exact scientist, he avoided confrontations among his porters or with indigenous peoples, neither killing any...
and, as a result, is sometimes referred to as a "tommie". It is considered by some to be a subspecies of the Red-fronted Gazelle
Red-fronted Gazelle
The Red-fronted gazelle is a species of gazelle that is widely but unevenly distributed across the middle Africa from Senegal to north-eastern Ethiopia. It is mainly resident in the Sahel zone, a narrow cross-Africa band south of the Sahara, where it prefers arid grasslands, wooded savannas and...
and was formerly considered a member of the genus Gazella within the subgenus Eudorcas, before Eudorcas was elevated to genus status. Thomson's gazelles can be found in numbers exceeding 500 000 in Africa and are recognized as the most common type of gazelle in East Africa.
Description
Thomson's gazelles are 50 to 70 cm (19.7 to 27.6 in) tall and weigh 15 to 25 kg (33.1 to 55.1 lb) (females), 20 to 30 kg (44.1 to 66.1 lb) (males). They have light brown coats with white underparts and distinctive black stripes on the sides. Their horns are long and pointed with slight curvature. The white patch on their rump extends to underneath the tail but no further. A mistake sometimes made is the misidentification of Grant's gazelleGrant's Gazelle
The Grant's gazelle is a species of gazelle. Its populations are distributed from northern Tanzania to southern Sudan and Ethiopia, and from the Kenyan coast to Lake Victoria. Its Swahili name is Swala Granti.-Taxonomy and genetics:...
s as Thomson's gazelles. Although some Grant's do have the black stripe running across their sides, the white on their rump always extends above the tail.
Ecology
Thomson's gazelles live in Africa's savannas and grassland habitats, particularly the SerengetiSerengeti
The Serengeti ecosystem is a geographical region in Africa. It is located in north Tanzania and extends to south-western Kenya between latitudes 1 and 3 S and longitudes 34 and 36 E. It spans some ....
region of Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
and Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...
. It has narrow habitat preferences being confined to short grassland with dry firm footing. It does, however, move into tall grassland and dense woodland during migration. Gazelles are mixed feeders. In the wet seasons, gazelles eat primarily lush green grasses, but during the dry seasons it starts to eat more browse particularly foliage, bushes, forbs, and clovers.
Thomson's gazelles are dependant on short grass. Their numbers highly concentrated at the beginning of the rains since the grass grows quickly. They follow the larger herbivores like plains zebra
Plains Zebra
The plains zebra , also known as the common zebra or Burchell's zebra, is the most common and geographically widespread species of zebra. It ranges from the south of Ethiopia through East Africa to as far south as Angola and eastern South Africa...
s and blue wildebeest
Blue Wildebeest
The Blue Wildebeest , also called the Common Wildebeest, is a large antelope and one of two species of wildebeest. It grows to 115–145 cm shoulder height and attains a body mass of 168–274 kg. They range the open plains, bushveld and dry woodlands of Southern and East Africa, living for...
s as they mow down the tall grasses. At this time the gazelles spread out more. In the wild, Thomson's gazelles can live up to 10–15 years. Their major predators are cheetah
Cheetah
The cheetah is a large-sized feline inhabiting most of Africa and parts of the Middle East. The cheetah is the only extant member of the genus Acinonyx, most notable for modifications in the species' paws...
s, which are able to attain higher speeds, but gazelles can outlast them in long chases and are able to make turns more speedily. This small antelope-gazelle can run very fast, up to 70 kph (43 mph), and zigzag, a peculiarity which often saves it from predators. They are also preyed on by lion
Lion
The lion is one of the four big cats in the genus Panthera, and a member of the family Felidae. With some males exceeding 250 kg in weight, it is the second-largest living cat after the tiger...
s, leopard
Leopard
The leopard , Panthera pardus, is a member of the Felidae family and the smallest of the four "big cats" in the genus Panthera, the other three being the tiger, lion, and jaguar. The leopard was once distributed across eastern and southern Asia and Africa, from Siberia to South Africa, but its...
s, hyena
Hyena
Hyenas or Hyaenas are the animals of the family Hyaenidae of suborder feliforms of the Carnivora. It is the fourth smallest biological family in the Carnivora , and one of the smallest in the mammalia...
s, baboon
Baboon
Baboons are African and Arabian Old World monkeys belonging to the genus Papio, part of the subfamily Cercopithecinae. There are five species, which are some of the largest non-hominoid members of the primate order; only the mandrill and the drill are larger...
s, and crocodile
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
s. A noticeable behaviour of Thomson's gazelles is their bounding leap, known as stotting
Stotting
Stotting is a gait of quadrupeds, particularly gazelles , involving jumping high into the air by lifting all four feet off the ground simultaneously. This may occur during pursuit by a predator...
or pronking, used to startle predators and display strength.
Social behavior
During the wet season, a time when grass is abundant, adult male gazelles will graze extensively. They spread out more and more and establish breeding territories. Younger males usually spend their time in bachelor groups and are prevented from entering the territories. Females form migratory groups that enter the males' territories, mostly the ones with the highest quality resources. As the female groups pass though and forage, the territorial males may try to herd and are usually successful in preventing single females from leaving but not whole groups. Subadult males usually resort to fighting to establish dominance while adults are usually more likely to do rituals. If a bachelor male should be passing through a territorial male's region, the male will chase the offender out of his territory.When patrolling his territory, a male may gore the grass, soil, or a bush with his horns. Males will also mark grass stems with a pre-orbital glands which emit a dark secretion. Territories of different males may share a boundary. When territorial males meet at the border of their territories they engage in mock fights in which they rush towards each other as if they are about to clash but they don’t touch. After this, they graze in a frontal position, then in parallel and them in reserve and move away from each other while constantly grazing. These rituals have no "winner" but merely "ratify" the position of the boundaries between the territories. Territorial males usually will not enter another males territory. If a male is chasing an escaping female he will stop the chase if she runs into another territory but the neighboring male will continue the chase.
Reproduction and parental care
A male gazelle will follow a female and sniff their urinate to find out if she is in estrous, a process known as flehmen. If so, he will continue to court and mount her. Female Thomson's gazelles will leave the herd to give birth to single fawns after a 5–6 month gestation period. They are unusual among ungulates in that they can give birth twice yearly, rather than just once. When birthing, a female gazelle stands in a matter similar to when she is urinating and the newborn fawn drops to the grounds while the umbilical cord tears. The mothers then licks the fawn clean of amniotic fluid and tissues. In addition, it is possible licking also serves to stimulate the fawn’s blood circulation or for the mother to "label" the fawn with her scent so she can distinguish it from other fawns olfactorilyOlfaction
Olfaction is the sense of smell. This sense is mediated by specialized sensory cells of the nasal cavity of vertebrates, and, by analogy, sensory cells of the antennae of invertebrates...
. In the first six hours of the fawn’s life, it moves and rests with its mother but eventually turns away from its mother and lies down and hides in the grass. The mother stays in the vicinity of the fawn and returns to nurse it daily. Mother and fawn may spend an hour together walking and such before the fawn goes and lies back down to wait for the next nursing. Mother gazelles may associate with other gazelle mothers. However, the fawns do not gather into "kindergartens". Mother gazelles will defend their young against predators like jackals and baboons but not against larger predators. Sometimes, a female tommie can fend a male baboon off by headbutting him with her horns in order to defend her fawn.
As the fawn approaches two months old it spends less time lying out and more time with its mother. Eventually the lying out ends. Around this time the fawn starts eating solid food but continues to seek suckles from its mother. The pair will also join a herd. Young female gazelles may associate with their mothers for as yearlings. Young males may also follow their mothers, however as they reach adolescence they are noticed by territorial males and thus cannot follow their mothers into territories. The mother may follow and stay with him but eventually stops following him when he is driven away and the male will them join a bachelor group.
Status
The population estimate is around 550 000. There has been a population decline of 60% from 1978–2005. Threats to Thomson’s gazelles are tourist impacts, habitat modification, fire management, and road development. Surveys have reported steep declines (60-70%) over periods of c. 20 years dating from the late 1970s in several places, including the main strongholds for the species: SerengetiSerengeti
The Serengeti ecosystem is a geographical region in Africa. It is located in north Tanzania and extends to south-western Kenya between latitudes 1 and 3 S and longitudes 34 and 36 E. It spans some ....
, Masai Mara
Masai Mara
The Maasai Mara National Reserve is a large game reserve in south-western Kenya, which is effectively the northern continuation of the Serengeti National Park in Tanzania...
and Ngorongoro. Thomson's Gazelle occur in a number of protected areas in their range. The core areas of the Serengeti-Mara population are protected by the Serengeti N.P. and Masai Mara N.R., where the only land use allowed is wildlife tourism.
Further reading
- Gazelles and Their Relatives by Fritz Walther (1984)