Giraffes sleep an average of two hours a day

While humans need 7-9 hours of sleep, an adult giraffe gets by on an average of 2 hours a day — some field studies have recorded even less.

That sleep is split into short episodes lasting just a few minutes each, often taken standing up, with brief, deeper sleep phases of only a few minutes at a time, sometimes with the neck curled back over the body.

The mechanism makes evolutionary sense: a giraffe is a large animal that’s slow to get up, and long, deep sleep on the ground means a serious risk of death in an environment full of predators.

The bigger picture: this is an extreme example of how predation pressure can shape physiology — other plant-eating animals on the savanna show a similar, if less extreme, pattern.