Giraffe pelvis, though relatively short, has an ilium that is outspread at the upper ends. A giraffe has only two gaits: walking and galloping. Walking is done by moving the legs on one side of the body at the same time, then doing the same on the other side. When galloping, the hind legs move around the front legs before the latter move forward, and the tail will curl up. The animal relies on the forward and backward motions of its head and neck to maintain balance and the counter momentum while galloping. The giraffe can reach a sprint speed of
Giraffe to reach the leaves of tall trees. This theory was eventually rejected, and scientists now believe the giraffe's neck arose through Darwinian natural selection—that ancestral giraffes with long necks thereby had a competitive feeding advantage (competing browsers hypothesis) that better enabled them to survive and reproduce to pass on their genes. The giraffe genome is around 2.9 billion base pairs in length compared to the 3.3 billion base pairs of the okapi. Of the proteins in giraffe and okapi genes, 19.4% are identical. The two species are equally distantly related to cattle, suggesting the giraffe's unique characteristics are not because