Many young giraffes, called calves, die from lion attacks during their first year of life. Once a giraffe reaches adulthood its height is often enough to protect it from lions. Adult giraffes, however, must still be careful of lions when they are bending down to drink water or rest. Usually giraffes will drink or rest in shifts so that at least one giraffe is always on the lookout for approaching predators.
The giraffes' height and excellent vision give them a wide view of the grasslands where they live, making it easy to spot predators from a distance. Some scientists believe that other animals—such as zebras, antelope, and wildebeests—often congregate near giraffes to take advantage of their ability to see danger from a distance. The giraffe could be considered the early warning system of the African grasslands.