how does the giraffe sleep

standing only

As far as I know, the giraffes sleep in group, and there's always a giraffe work as guard who can prevent the group from sudden attack of jungle animals like leopard.

Giraffes don't need pillows, because they sleep less than 2 hours each day standing up! Giraffes sleep in short bursts. Some scientists speculate that they "semi-sleep" while they are eating as well – a form of "zoning out. http://www.nhlbi.nih.gov/health/public/sleep/starslp/teachers/answers.htm But during deep sleep the neck is bent backward like a handle, the chin touches the ground behind the tarsal joint of the stretched hind leg, and the lower jaw rests on the shank. http://www.huntingsociety.org/GiraffeInfo.html