The Many Ways of Sleeping

6 The Many Ways of Sleeping Sleep. It's something that all mammals, birds, and reptiles do. We all need sleep, but different species have adapted to it in different ways, according to the conditions of their environments. You can, in fact, tell a lot about an animal by studying the way it sleeps. For example, for humans, it's natural to lie down on one's back or stomach and drift off to sleep. That's easy enough to do when you're at the top of the food chain and don't have natural enemies. Lying down to sleep leaves one open to attack, so only those creatures with few enemies regularly sleep like that. Caution and safety are at the forefront of many animals' minds when sleeping. Did you know that elephants sleep standing up? The same is true for cows, horses, and sheep. When these animals go into the dream state, they lie down. But, the majority of their sleep occurs while they are standing.

Many of these larger land animals rely on speed in flight to protect them from predators. Their ability to lock their leg joints and sleep while standing gives them an advantage if they come under attack while snoozing. Imagine the disadvantage if they had to wake from sleep while lying on the ground and then rise to their legs before taking flight. Birds sleep in a similar way, and it is assumed, for similar reasons-safety. They simply lock their claws around their perch, and go to sleep. This allows them to enter the sleep state in a relatively safe location, high up in a tree. As a rule of thumb, the smaller the animal is, the moresleep it needs. Giraffes need only two hours of sleep per day while bats sleep for a whopping twenty hours every day. Fully developed humans require about eight hours a day, which is a couple of hours more than their closest cousins, chimpanzees. No doubt about it, all animals need sleep. And they have many ways to get it.