Dave Taylor's African Safari: Trophic Level II - The Herbivores - Masai Giraffe

Dave Taylor's African Safari: Trophic Level II - The Herbivores - Masai Giraffe - Page 37

Trophic Level II - The Herbivores
Masai Giraffe
Page 37

Giraffa camelopardiis tippelskirchi

Length: 3.5 m - 4.8 m (11.4-16’)

Height: 3.5 m - 4.7 m (11.4-15’) female, 3.9 m -5.2 m (13-15’) male

Tail: 76 -110 cm (30-43")

Weight: 450- 1 800 kg (992-3968 lb.) female, 1 800- 1 900 kg (3,968-4,189 lb.) male

Status: Declining but not endangered. Masai giraffe are well protected in East Africa’s reserves and parks. Two other races of giraffe are also found in the region. Rothchild’s giraffe is found in a few parks in Kenya where it was imported from Uganda in order to save the race from the Uganda civil wars a few decades ago. It is considered to be threatened. Kenya’s other native giraffe, the reticulated, is found to the north. It, too, is threatened.

Habitat: Giraffe are browsers and are found in habitats where trees are present; savannas, open woodlands and seasonal flood plains. They do not like heavily forested areas and prefer areas where fire, elephants or soils create conditions of grassland and forest.

Food: Giraffes are the largest ruminants.

Giraffes feed on over 100 species of trees but Acacia, Commiphora and Terminala trees are the most commonly sought ones (see Trees: Symbiotic Relationships). During the wet season, when there is plenty of moist, rich browse available, giraffe are spread out widely over the woodlands. In the dry season, they concentrate where evergreen* trees grow.

(*Author’s note: Evergreen trees are not necessarily conifers. In the tropics and sub-tropics, many deciduous trees keep their leaves all year round. On the dry plains, these "evergreens" grow along river banks or in places where their roots are able to reach the water table.)

The constant browsing by giraffes on the acacia trees prunes the trees and gives them a peculiar umbrella shape. Trees that are not browsed by giraffe, or trees found in areas where giraffe are not found, do not have this appearance. Where fire and giraffes combine to be factors, an "acacia lawn" is created. Here, there are no young acacias growing and all of the mature trees look the same.

Giraffes will also browse on much smaller trees. In Nairobi National Park, Kenya, their favorite tree is the whistling thorn (Acacia drepanolobium). Because these trees are smaller, the giraffes browse on their tops and prevent them from growing taller. This explains the trees’ almost uniform height in this park. The same species of tree is found in the Serengeti but is not browsed to the same extent because there is a greater variety of trees found here than in Nairobi National Park. Nonetheless, these trees also show the effect of the giraffe’s feeding habits. (Whistling thorns fed on regularly by giraffe are about 2 meters (6.5’) high. Where there are no giraffes, the trees are a meter taller.)

Ruminating Giraffes Due to the higher quality of their food, giraffes require about half the intake that grazers must take in. A large bull giraffe eats about 33 kilograms (73 lb.) of browse a day. Giraffes, in general, spend five hours a day ruminating (chewing their cud). One female giraffe chewed her cud an average of 44 chews per cud. Female giraffes spend about half of their 24 hour days feeding. Bulls feed a little less than this. Bulls feed less probably because they are able to access better food in locations that cows avoid due to predators.

On the other hand, bulls spend 22% of their day walking. Cows spend only 13% of their day doing this. The difference probably has to do with the time bulls spend looking for cows in heat.

Giraffes will drink water, but it is dangerous thing for them to do. Getting that long neck down to water level requires that they spread their front legs far apart and then lower their head to the river. In the Serengeti-Mara ecosystem, giraffes are seldom observed doing this. Here, they probably get most of the water they need from the vegetation they eat. In Nairobi National Park, where giraffes are well studied, one researcher saw giraffes drink only 20 times in two years!

Social System: Giraffes have a very loose social structure. Herd loyalty is virtually non-existent. As the largest ruminants, giraffes have little to fear from most predators and wander about as they choose. If there is a group of giraffes in one location, it is probably because the food source has attracted them, and not because they are moving together.

They do not hold a territory. Giraffe will stay within a limited home range. The size of range varies with the quality of the browse. Unlike most other ruminants, the male’s range is bigger than the female’s.

Giraffes within a home range know each other. Among females there is no hierarchy, but males definitely know their place among other males. Dominant males can displace a subordinate male just by approaching him. Giraffes usually associate in mixed herds. Cows do seem to have a preference for other cows and bulls associate with other males more than they do with cows. A female will stay with other females longer than she will stay will a bull. Females with young will stay out on the plains while bulls tend to prefer more heavily forested areas.

Long Distance Social Gatherings

Giraffes are quite comfortable some distance away from other giraffes. Their large size permits them to wander away from the herd more freely than a wildebeest or zebra would comfortably do. A herd of giraffe might well be spread over half a kilometer (.3 miles) or more and still be a herd. Even at rest and clumped together, giraffe are normally at least 20 meters (66 feet) apart.

A bull’s rank in giraffe society is determined when they are adolescents. They spar by swinging their necks into the opponent’s. This behavior is called "necking". In the wild, it appears to be only engaged in by males. A giraffe’s neck weighs more than an average adult human weighs and can pack quite a wallop if the battle is serious. There have been reports of one giraffe knocking another off its feet.

A myth about giraffes is that they are sentinels that other herd animals seek out. The thinking was that the long-necked giraffe would spot danger and warn the others. This does not seem to be true. Giraffe seldom, if ever, warn other giraffe of danger and when they do, the other giraffe seem to ignore it. Nor do they warn other species that a predator is approaching. The giraffe just moves quietly off.

Behavior: Giraffes give birth to one calf after a gestation period of 14 to 14.5 months. The time between calves is about 16 months. They give birth standing up. Serengeti giraffes tend to give birth in the same general location as they used before. The newborn calf weighs approximately 120 kilograms (264 lb.). It lies out for the first week or so, for half the day and most of the night. Its mother stays within 11 to 25 meters (36-116’) of the calf for the first two weeks.

Giraffe females will leave their young in a crèche with other calves of the same age. Mother will go off to feed or seek a mate while the youngsters browse on their own. Almost 75% of young giraffe are killed by predators during this period of time when there is no adult to protect them.

The cow will return to feed her calf a couple of times during the day. Her presence deters most predators, most of the time. Her hooves are the size of dinner plates and she can deliver a powerful kick with her long legs. A single kick has been known to kill a lion.

Predators: Lions are the main predators of giraffe. They prefer the calves but will take adults from time to time. Spotted hyenas will take an undefended or injured calf.

Select a Page:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42