Because of their long necks and legs, giraffes are the tallest animals
in the world. Patch coloration and shape can vary within their extensive
habitat range. Females are distinguished from males in that the females
have shorter, inward-curving horns. In both sexes, a long mane of
stiff, brushlike hairs extends from the back of the head to the
shoulders. Giraffes exhibit a unique, fluid gait. When walking, the fore
and hind legs on the same side appear to move almost in unison. Swift
and fleeting, giraffes can gallop up to thirty-three miles per hour.
Their gallop can be described as a motion in which the front legs move
together and their hind legs move forward and outward, enveloping the
forelegs in a unique rhythmic pattern. Long and graceful, their sleek
necks swing back and forth rhythmically with their legs. The neck has
remarkable range of motion. A system of blood vessels and valves in the
neck protects the brain and reduces blood pressure when the animal
lowers its head.
Diet
Although some may feed at night,
giraffes are classified as herbivorous diurnal eaters. They are
browsers, and competition for food is greatly reduced because of the
height at which they feed. The male feeds at greater heights, with his
head stretched upward, whereas the female feeds at lower heights, often
bending her head and neck to reach the leaves. Giraffes feed mainly on
the highly nutritious leaves, fruit, and flowers of acacia trees. Their
long, dexterous tongues strip leaves from the acacia twigs. Giraffes
often consume soil and bones to balance the phosphorus and calcium in
their blood. When feeding on sprouted vegetation and when drinking
water, giraffes splay their front legs and bend their knees. In such a
position, they are vulnerable to predators, especially lions. Giraffes
can go without water for days.
Protection, Defense, and Communication
Generally docile creatures, giraffes may kill other animals with a kick
of a fore or hind hoof. Their heads, used like a knight's mace, land
formidable blows on the body or legs of opponents. The effective use of
their heads as weapons is enhanced by the physical structure of horns
and knobs. The skull bone is solid and thick, so that its force can
result in a fatal blow. The giraffe's own head is protected by extensive
sinuses, which absorb shock. Giraffes snort, grunt, bleat, bellow, and
moo to communicate. Because of their height, giraffes' sense of smell is
not as keen as other animals. However, their sensitivity to sound and
their visual acuity more than compensate for their underdeveloped sense
of smell.
Reproduction and Birth
Mixed herds of variable
numbers have been recorded in the field. Old males are often solitary.
About a day before mating, the female becomes sexually attractive. At
the onset of mating, the male licks the female's genitals and catches
her urine on his tongue. Chemical signals in her urine are detected by
flehmen as the male's Jacobson's organ becomes activated. The male
remains with the female in heat unless he is displaced by a
higher-ranking challenger. The female gives birth in cover, with her
back legs bent to reduce the height from which the calf falls.
Initially, the mother is alone with her calf, but later she may form a
nursery group assisted by other females. The calf stands within five
minutes of birth and suckles within the hour. The calf becomes
independent of the mother around the sixteenth month. Play behavior,
called nose-to-nose sniffing, between the young cements social bonds
between them.
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