Eli5: How do giraffes function on such little sleep?



I’ve recently read that giraffes only require 5-30 mins of sleep per 24 hours, and they often take this in 5 min chunks due to the risk of predators.
But how do they survive off such little sleep?

In: Biology

It is well worth noting that many animals use the two halves of their brains in sequence rather than in parallel: one half of their brain sleeps at a time, meaning that they don’t need as much “true sleep” because they are often half asleep in a very literal way.
Sharks don’t truly sleep at all and cats can sleep up to twenty hours a day. The amount of sleep one needs is different between species due to behavioral and metabolic differences that have evolved over millennium to suit an ecological niche.