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Grant's gazelle
| FACT FILE: |
| Swahili
Name: |
Swala
Granti |
| Scientific
Name: |
Gazella
granti |
| Size: |
30 to 36
inches at the shoulder |
| Weight: |
100 to 145
pounds |
| Lifespan: |
12 years |
| Habitat: |
Open grass
plains |
| Diet: |
Herbivorous/browsers/grazer |
| Gestation: |
7 months |
| Predators: |
Humans, all
major predators |
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Grant's gazelles resemble Thomson's gazelles, and the two
species are often seen together. They are similarly colored and
marked, but Grant's are noticeably larger than Thomson's and
easily distinguished by the broad white patch on the rump that
extends upward, beyond the tail and onto the back. The white
patch on the Thomson's gazelle stops at the tail. Some varieties
of Grant's have a black stripe on each side of the body like the
Thomson's gazelle; in others the stripe is very light or absent.
A black stripe runs down the thigh.
Physical Characteristics
The various types of Grant's gazelle differ mainly in
color and in the size and shape of the horns. Grant's are large,
pale, fawn-colored gazelles with long legs. The males are larger
and heavier and their horns longer than the females.
The lyre-shaped horns are stout at the base, clearly ringed
and measuring from 18 to 32 inches long. The width of the spaces
between the horns and the angles of growth differ among the
various types of Grant's gazelles. One type, in northwest
Tanzania, has widely diverging horns, with the tips directed
downwards.
On the females black skin surrounds the teats, with white
hair on the udder. This probably helps the young recognize the
source of milk. When a fawn is older and moving about with its
mother, the dark stripe on the white background may serve as a
beacon for it to follow.
Habitat
Grant's gazelles are especially fond of open grass plains, and
although they frequent bushy savannas, they avoid areas of high
grass.
Behavior
Grant's gazelles may remain in areas where food is plentiful.
Mature males establish territories they may hold as long as
eight months. A male tries to detain the female herds of 10 to
25 individuals as they pass through these territories while they
move about to feed. At the same time males chase off rival males
and try to mate with females in estrus.
Grant's gazelles have developed several ritualized postures.
For example, the territorial male stretches and squats in an
exaggerated manner while urinating and dropping dung. This
apparently warns other males to stay away and reduces the number
of confrontations. Younger males will fight, but as they grow
older the ritualized displays often take the place of fights.
When fighting does occur, it also is ritualized. It starts with
"pretend" grooming, repeated scratching of the neck and forehead
with a hind foot and presenting side views of the body. If
neither combatant is intimidated, they may confront one another
and clash horns, trying to throw the other off-balance.
Diet
The gazelles vary their diet according to the season. They eat
herbs, foliage from shrubs, short grasses and shoots. Grant's
gazelles are not restricted to certain habitats by a dependency
on water, but obtain the moisture they need from their food.
Grant's have unusually large salivary glands, possibly an
adaptation for secreting fluid to cope with a relatively dry
diet. They typically remain in the open during the heat of the
day, suggesting an efficient system to retain the necessary
fluid in their bodies.
Caring for the Young
Breeding is seasonal, but not firmly fixed. Gestation is
approximately 7 months, and the young are born in areas that
provide some cover. The newborn fawn is carefully cleaned by the
mother who eats the afterbirth. Once the fawn can stand up and
has been suckled, it seeks a suitable hiding place. The mother
watches carefully and evidently memorizes the position before
moving away to graze. She returns to the fawn three to four
times during the day to suckle it and clean the area. The
lying-out period is quite long-two weeks or more.
The fawn eats its first solid food at about 1 month, but is
nursed for 6 months. Grant's become sexually mature at about 18
months. By that time the young males will have joined an
all-male bachelor herd, but it will be some time before they
become territory holders, if at all. Males from the bachelor
herds challenge the territorial males, but only the strongest
win territories, which they mark with combined deposits of dung
and urine.
Predators
All the major predators kill Grant's gazelle, but cheetahs and
African hunting dogs are the most prevalent. In some areas
jackals prey on the young. Because of its adaptation to
semi-arid and subdesert ranges as well as its good meat and
valuable skin, Grant's gazelle has been one of the species that
scientists consider as a potential source of protein for humans.
Did you know?
- The only relatively long-lasting relationship in gazelle
society is that of a mother and her most recent offspring.
- Grant's are gregarious and form the usual social groupings
of small herds of females with their offspring, territorial
males and all-male bachelor groups. Membership in these groups
is temporary.
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