Giraffes rest their long necks on their body or hind legs. They sleep for short periods, often only minutes at a time, for a total of about 4.5 hours (or much less) in a 24 hour period. They can also sleep standing up. By comparison, humans typically sleep for 8 hours. Did you know that although giraffes reach 18 ft in height, their neck has the same number of vertebrae as ours!