Giraffes are very susceptible to becoming prey, so they must sleep in short bursts. They also cannot lay down. The giraffes curl their neck up and remain standing while taking their naps. They may sit periodically while sleeping.
Female giraffes also give birth while standing up. A giraffe's body must work much harder than most animals due to its large size and long neck. Its heart has to work twice as hard to force blood to its brain.Learn more about Giraffes