Reticulated Giraffe


ORDER: Artiodactyla

FAMILY: Giraffidae

GENUS: Giraffa

SPECIES: camelopardalis reticulata

DESCRIPTION:
Head-body length 12-15 ft.; height to horn tips 15-18 ft.; weight 1700-4200 lbs (males). Females are a foot or two shorter and a couple of hundred pounds lighter. Both sexes have horns, although the females horns are smaller. G.c. reticulata is a bit smaller than the other subspecies. Varieties are told apart largely by pattern. Reticulated are characterized by large polygons separated by cream-colored lines rather like a large net thrown over a colored ground, hence the name"reticulated" giraffe. Color ranges from tan to deep chocolate brown, especially in old males who tend to darken as they age.

GEOGRAPHICAL RANGE AND HABITAT:
Open woodland and wooded grassland throughout sub-Saharan Africa. Reticulated giraffe are confined to north-eastern Kenya, eastern Sudan and Eritrea.

DIET:
Highly selective browsers feeding primarily on a variety of Acacia and Combretum species. Over a hundred species may be eaten, depending on what is seasonally available. Although mostly leaves and shoots are taken, giraffe also eat flowers, vines and herbs. Giraffe have also been seen to eat weaver-bird nests with young inside, and may chew on bones, perhaps to gain additional minerals. An average of 16-20 hours per day are spent feeding and up to 140 lbs of fresh browse are taken. Thorns do not seem to be a deterrent to feeding; the long, prehensile, muscular tongue (which can be extended up to 18 inches), thick, gluey saliva, and special upper palate shape enable the giraffe to process thorny foods. They are ruminants with a 4-chambered stomach.

LIFE CYCLE/SOCIAL STRUCTURE:
Giraffe form scattered herds, the compositions of which are constantly changing. Although gregarious, the individual is the social unit in giraffe society. Home ranges are large, about 46 sq. miles. Bulls are non-territorial and exhibit a dominance hierarchy. Young bulls determine dominance with "necking displays Unknown nomadic males may stimulate serious fighting with sledgehammer blows being exchanged, using the side of the head. Dominant males father most of the young. Males become sexually mature at about 42 months but seldom have a chance to breed until 8 or more years old. Females first conceive in their fifth year of age. Gestation is about 15 months. Calves are born in special calving grounds from a standing female, thus dropping some 6 feet to the ground. Birth weight is 100-150 pounds; height is 6 feet. They can stand on wobbly legs about five minutes after birth and begin to feed about 20 minutes later. Groups of calves may be found together waiting for their mothers to come by to nurse. Offspring begin browsing in their first month and are rarely observed to suckle after they start eating leaves. First year calf mortality is about 58%. Lions are the major predator, but calves may be taken by hyenas, leopards and African wild dogs. Life expectancy is 25 years.

SPECIAL ADAPTATIONS:
Giraffe drink water if it is available but can go weeks without it; they rely on the morning dew and the water content of of their food. Their very long necks are an adaptation to feeding at high levels in the treetops. The neck veins contain valves and a network of tiny veins (rete mirabile) to prevent blackouts when the animal lowers its head to drink. In addition to keeping track of predators, their extreme long-range visual acuity enables visual communication with other giraffe over several miles. Giraffe can run at speeds up to 35 mph.

INTERPRETIVE INFORMATION:
There are a number of misconceptions about giraffe. One is that they cannot make any sound. Although generally quiet, they have been heard to grunt, snort and bleat. Another is that they never lie down. In fact, they often lie down to sleep, with head and neck lying across the flanks, although these sleeping periods tend to be brief - one to twenty minutes. The length of the forelegs in relation to the hind has been exaggerated. In fact, they are both about the same size (the foreleg is 1/10th longer than the hind). It is the high dorsal spines of the shoulder which give the false impression of a difference in limb length. They have only seven vertebrae in their neck, the same number as man. Horns are bony masses covered with skin and tufts of hair and are not really horns at all. They may represent relics of pedicels from which antlers grew ages before (since giraffe are fairly closely related to deer). Conspecific fights are effected by neck wrestling and head banging; defense against predators is characterized by striking out with the forefeet. Males have extra bone deposits on their skulls for fighting.

OUR ANIMALS:
4 Males. 4 Females. In our current collection, there are two females and one male that came here from other zoos. All the others were born here.

STATUS IN WILD:
Giraffe are still common in East and South Africa, although their distribution in West Africa has been fragmented by poaching. The tourist trade in giraffe hair bracelets has encouraged poaching.

BIBLIOGRAPHY:

  1. Dagg, Anne Innis and J. Bristol Foster. The Giraffe: Its Biology, Behavior, and Ecology. Van Nostrand Reinhold Company, 1976.
  2. Kingdon, Jonathan. East African Mammals: An Atlas of Evolution in Africa. The University of Chicago Press, 1979.
  3. Macdonald, David. The Encyclopedia of Mammals, Facts on File Publications, New York, 1984.
  4. Nowak, Ronald. 1991. Walker Mammals of the World, 5th Ed, Vol II. Johns Hopkins University.

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