African Animals, Serengeti, Ngorongoro, and Lake Manyara wildlife

The tallest of all land living animals, the Giraffe is a very common sight in the Serengeti, though they are notably absent from the Ngorongoro Crater (due to the shortage of acacia to browse). Males can be 4.8 to 5.5 metres tall and weigh up to 900 kilograms. Females are generally slightly shorter and weigh less. Of the 9 subspecies of giraffe, differentiated by color and pattern variations and range, the one that inhabits the reserve is known as Masai or Kilimanjaro Giraffe (G.c. tippelskirchi). It has characteristic jagged-edged, vine-leaf shaped spots of dark chocolate on a yellowish background.

Giraffes are famous for their long necks which allow them to browse on the leaves of trees, and elongated forelegs (which appear much longer than the hind legs, but in reality, are only 1/10th longer). The bony structure of the neck is essentially unchanged from that of other mammals: there are no extra vertebrae, but each of the seven bones is greatly enlarged. Bone constitutes the bud-like horns called ossicorns, which are covered with the Giraffe's skin like the rest of the skull.

In its native country the Giraffe browses on the twigs of trees, preferring plants of the Mimosa genus; but it appears that it can without inconvenience live on other vegetable food. A Giraffe can eat 63 kilograms (140 pounds) of leaves and twigs daily.

Modifications to the Giraffe's structure have evolved, particularly to the circulatory system. A giraffe's heart, which can weigh up to 24 lb (10 kg), has to generate around double the normal blood pressure for a large mammal in order to maintain blood flow to the brain against gravity. In the upper neck, a complex pressure-regulation system called the rete mirabile prevents excess blood flow to the brain when the Giraffe lowers its head to drink. Conversely, the blood vessels in the lower legs are under great pressure (because of the weight of fluid pressing down on them).

The pace of the Giraffe is an amble, though when pursued it can run extremely fast. However, the small size of its lungs prevents it from supporting a lengthened chase. The Giraffe defends itself against threats by kicking with great force. A single well-placed kick of an adult giraffe can shatter a lion's skull or break its spine.

The long necks do allow a giraffe to eat from the tops of trees. However, since female giraffes are not as high as male giraffes and tend to feed from much lower heights than their male counterparts, it is hard to say that they need the long necks for metabolic reasons. Furthermore, the additional length that helps a giraffe reach the top food sources makes it incredibly difficult for the same creature to drink. While the ecological niche which at least male giraffes utilize is only used by a single other species, the African Elephant, there has been no selective forces to maintain the length of the giraffe's neck for a long time. It may be that the long neck originally evolved when the benefit of filling the ecological niche was more pronounced due to the presence of other giant ungulates in Africa, which are now extinct.

In addition to the remarkably long neck, giraffes have enlarged forelegs. These legs make it possible for giraffes to move swiftly and defend themselves against predators. It is unknown whether or not the size of the giraffe's neck, working in combination with the leg length, may provide a biomechanical advantage in defending against lion attacks.

Finally, it has been observed that males use their long necks, not just for feeding, but for combat and competition. Indeed, sexual dimorphism is strongly represented among giraffes with females having shorter, lighter necks than males. Among females, the neck and head mass levels off after about ten years of age, while the same organs in males will continue to grow throughout the twenty-plus year lifetime. The males engage in necking combat. These battles can be fatal, but are more often less severe. The longer a neck is, and the heavier the head at the end of the neck, the greater force a giraffe will be able to deliver in a blow.