We can survive longer without food than we can without sleep. Typical individual spends a third of the life sleeping. That is 25 years or even more! Sleep is very important for healthy life. People whose normal nightly sleep duration is either very short (less than 4 hours) or very long (more than 9 or 10 hours) have a higher than average risk of dying prematurely. But that does not apply for animals. Their sleeping period is very different. The most sleepiest animal on the planet can sleep around 22 hours (out of 24) and animal that sleeps the least (giraffe) only 1.9 hours. That’s a big difference.