Classification and Range
Grant's gazelles are in the order Artiodactyla, or even-toed ungulates (hoofed mammals). They belong to the family Bovidae, which includes antelope, cattle, sheep and goats. G. granti is in subfamily Antilopinae, which has 14 genera. Members of the subfamily Antilopinae are "true antelopes". They are small- to medium-sized, graceful creatures with slender legs and rather long necks. The horns are usually present in both sexes, but may be reduced or absent in females. All 16 species of gazelles are members of the genus Gazella.
Grant's gazelles live in southeastern Sudan, southern Ethiopia,southwestern Somalia, northern Tanzania, northeastern Uganda and Kenya.
Grant's gazelles inhabit semi-desert areas, open savannas and treeless plains. Herds avoid tall grass if they can. They occasionally roam in acacia thicket country, but only if the area has many paths and open swaths.
Grant's gazelles are long-legged, heat- and drought-tolerant antelopes. They are stocky and larger than most gazelle species, with males standing between 33 -36 inches (8-91 cm) tall, and a body length of 61-65 inches (155 -166 cm). The weight of males ranges from 128-180 pounds (58-82 kg), with an average of 143 pounds (65 kg). Females stand 29-32 inches (74-81 cm) tall and have a body length of 55-59 inches (140 -150 cm). The weight of females ranges from 84-148 pounds (38-67 kg), with an average of 99 pounds (45 kg). For both sexes, the tail length is 8 -11 inches (20-28 cm).
They have a reddish-tan coat with a white underbelly and inner legs, along with a white rump patch framed in black. The belly coloration is most conspicuous in arid-zone species, which need to deflect away the high temperatures radiated upwards from ground surfaces. Grant's gazelles have a characteristic white stripe on their face running from their horns to their muzzle, framed with a black edge. (this trait distinguishes Grant's gazelle from other gazelles). Females may have a black stripe outlining the snow-white rump patch. Some Grant's gazelles have diagonal black bars on the sides of their flanks. The ears are long and pointed at the tip. G. granti has keen vision and hearing. Both sexes have S-shaped, ringed, unbranched horns that curve backwards and the forwards to turn inward at the tips. The horns are 18-31 inches (46-78 cm) in length, and the record length of horns was 32 inches (81 cm). A male's horns are more heavily ringed.
In captivity and the wild, their life span is 12 to 14 years.
In the wild: Grant's gazelles graze and browse the greenest plant material, preferring short herbs and the leaves of shrubs. They eat grasses when leaves and herbs are unavailable. They also occasionally eat fruit.
At the zoo: Primarily alfalfa, timothy hay, and commercially prepared herbivore diet, with occasional fruits and vegetables as treats.
When breeding season begins, Grant's gazelles leave their normal pattern of mixed-sex groups as males begin to define breeding territories, which range from 550 -2,200 yards (503 -2,012 m) in diameter. To define these territories, males have small glands all over their body. They have facial, groin, "knee" and foot glands. In contrast, larger species of gazelles usually don't mark their large home ranges, and have only rudimentary face glands. However, breeding male Grant's gazelles also mark their territories with ritual displays of urination and defecation. They will defend their boundaries from challenging males using anything from ritualized threat displays to intense fighting.
Males are slower to fight than other smaller gazelle species, but fight longer and harder if they do engage. Territorial males defend only against other breeding males, and are tolerant of visiting, non-breeding males. Territory defense begins with two males approaching or standing parallel, facing opposite directions, with heads tilted slightly away from each other. They whip their heads toward each other, tilting their chins up to display their horns. They may repeat this sequence several times. The second level of threat is to tuck their chins, while keeping the horns vertical. The third level is head down, horns pointing horizontally. If horn displays progress to fighting, their heads are close to the ground, horns forward. Opposing males try to catch the other animals' horns to throw him.
Breeding males attempt to convince females to enter and remain in their territories through behavioral displays, but they will not follow a female into another male's territory if she decides to leave.
Generally, birth peaks in January and August after a gestation of about 6 months. The female ventures into tall grass to give birth to her single calf. Directly afterwards, the female cleans the calf and eats the afterbirth. After the calf nurses, it remains hidden in the tall grass as its mother grazes nearby. The female walks around the calf, memorizing its hidden location. She checks it from many angles before moving away, since she must periodically return to the calf to nurse. Females often vigorously defend their young. Females with newborn calves remain apart from herds, but rejoin them as the calves grow older.
Although gregarious throughout most of the year, Grant's gazelles do not form lasting adult relationships. Herds can be females, females and young, bachelor groups, or, outside the breeding season, mixed. Herds of females wander in annual home ranges of about 115 square miles (298 sq. km), while solitary males defend territories of 20 acres (8.1 ha) to 38 square miles (98 sq. km) in diameter. Females with newborn calves and territorial males do not join the herd.
Grant's gazelles live at higher densities in richer habitat. Their flexible social system is well-adapted to take advantage of scattered and changing food supplies throughout the year. A herd in an area with scattered or sparse vegetation may have just 10 -15 animals. However, as the herd moves or the area becomes lush during the rainy season, more groups or individuals may join until their numbers swell to several hundred. Then, when food resources decline again, the herd breaks up.
Grant's gazelles feed at night, when humidity is higher. During early rains, they incorporate grasses into their diet.
Leaping For Their Lives
Grant's gazelles, along with all other gazelle species, engage in a unique behavior called "pronking." When a gazelle pronks, it leaps repeatedly straight up into the air with hunched shoulders, and lands on all four feet at once. The reasons for this behavior are not precisely known, but it may be associated with play, serve as an alarm signal to the rest of the herd, or allow the gazelle to search for predators lurking in tall grass. Pronking may also serve as a warning to predators that they shouldn't waste their time chasing that particular animal. A pronking gazelle advertises strength and stamina. Recognizing the obvious health of its prey, a hungry lion may look elsewhere for its next meal.
Beat the Heat!
If the body temperature of a Grant's gazelle is higher than the brain can tolerate, the animal pants rapidly, and blood passes through the vessels of the moist nasal mucous to be cooled by evaporation. The cooled blood drains to the sinus space below the brain, and surrounds the carotid artery, cooling the blood on its way to the brain. This mechanism also occurs in other bovids, including domestic sheep. Grant's gazelles also have muscular flexibility whereby they can control the airflow for extra efficiency. Additionally, the nasal bones do not extend into the lower muzzle. This lack of a constricting tube probably allows the nostrils their great flexibility; this likely improves temperature regulation.
Location at the Zoo
Grant's gazelles can be seen in the zoo's award-winning African Savanna exhibit. Other species you will find there include the hippopotamus, giraffe, fringe-eared oryx, zebra, and lion.
The Grant's gazelle remains widespread, with a total population of about 140,000. However, its population is slowly declining over 75% of its range. Although the Grant's gazelle is not considered an endangered or threatened species, the same cannot be said for other gazelle species. Two of the 16 known species in the genus Gazella are thought to be extinct in the wild; they are G. rufina and G. saudiya . Several other gazelle species are listed as endangered or threatened, including G. dama, G. dorcas, G. gazella and G. rufifrons. Gazelle populations are negatively impacted by poaching, habitat loss due to the expansion of agriculture, and competition for food with livestock.
Grant's gazelles, along with other large herbivores, insects, and rodents all play important roles in the development, maintenance and ecological structure or composition of the African savanna. Besides being an important food source for large predators, grazing animals actually create and maintain the grasslands they depend on! Grasslands have evolved under the grazing pressures of ungulates since the Cenozoic Era (65 million years ago to today). The most critical growth tissues is from the base of the grass, at or below ground surface. This protects grasses from the heaviest grazing or fire. Also, when animals clip away at the top of the grass or eat the leaves, the grass responds by directing energy to other parts of the plant and new growth is stimulated. Moderate grazing actually improves the productivity of grasses. It makes room for new, young tissue growth in grasses.
If grazers cannot perform their ecological role, the structure of grasslands changes. Woody vegetation invades the area and the habitat changes, or the region is converted to a desert as a result of overgrazing by domestic cattle with typically limited ranges. With these changes in the savanna also comes the further loss of other animals that depend on grassland habitat. Paradoxically, Grant's gazelles may actually benefit from overgrazing by cattle. As cattle feed and reduce the amount of available grasses, herb vegetation overtakes the abused grazing site. In turn, this generates an abundance of food for the Grant's gazelle, which prefers this new growth.
Woodland Park Zoo Is Helping-With Your Support!
For many animals, flexible and sustainable conservation programs are essential. Partnerships with other zoos can support healthy captive populations, while in-situ fieldwork can provide successful on-ground solutions. There are several other field-based conservation projects supported by Woodland Park Zoo that aim to help animals and plants in the savanna habitat of the Grant's gazelle.
Each in-situ project supported by the zoo aims to provide a broad, holistic approach to conservation, encompassing research, education, habitat and species preservation. This includes comprehensive, cooperative strategies to link the needs of animals with the people who share their ecosystems.
How You Can Help!
Woodland Park Zoo contributes information to the captive breeding, husbandry and public awareness of this intriguing native species. The effort to save animal species requires cooperation and support at the international, national, regional, and individual levels. You can help in this cause. Join and become active in Woodland Park Zoo and other conservation organizations of your choice. Let your elected representatives know your views on protecting endangered species and wild habitats. Please do not buy products made from wild animal parts.
Contact Woodland Park Zoo at firstname.lastname@example.org to find out about ways you can support conservation programs at the zoo. Learn other ways you can help conserve wildlife and the habitats they require for survival by visiting our How You Can Help page.
Sources and Suggested Reading
Alcock, John, 1984. Animal Behavior, an Evolutionary Approach, 3rd Ed. Sinauer Associates, Inc. Publishers, Sunderland, MA. 596 p.
Kingdon, Jonathan. 1982. East African Mammals, Vol. III, part D. University of Chicago Press, Chicago, IL. 746 p.
Macdonald, Dr. David ed. 1984. The Encyclopedia of Mammals. Facts on File Publications, Inc., New York, NY. 895 p.
Nowak, Ronald M. ed. 1991. Walker's Mammals of the World 5th edition. The John Hopkins University Press, Baltimore and London. 1629 p.
Smith, Robert, 1992. Elements of Ecology, 3rd edition. Harper Collins Publishers, New York, N. Y. 617 p.
Spinage, C. A., 1986. The Natural History of Antelopes. Facts on File Publications, New York, NY. 203 p.
Silver, Donald M., 1997. African Savanna. McGraw-Hill Professional Book Group. 48 p.
The Ultimate Ungulate Page: http://www.ultimateungulate.com
The University of Michigan Animal Diversity Web: http://animaldiversity.ummz.umich.edu
Naturalia Zoo in the Wild: http://www.naturalia.org/ZOO/index.html
The Wild Habitat: http://library.thinkquest.org/11234/