Giraffe up. The calf emerges head and front legs first, having broken through the fetal membranes, and falls to the ground, severing the umbilical cord. The mother then grooms the newborn and helps it stand up. A newborn giraffe is tall. Within a few hours of birth, the calf can run around and is almost indistinguishable from a one-week-old. However, for the first 1–3 weeks, it spends most of its time hiding; its coat pattern providing camouflage. The ossicones, which have lain flat while it was in the womb, become erect within a few days. Mothers with calves will gather in
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