
não se aplica ás arboriculas

Moderador: mcerqueira
Question No. 19646 :
Do snakes have any eyelid and how they sleep? Thank you.
Sleep is a period of rest during which the sleeper loses awareness of his or her surroundings. Sleep, unlike a coma, is easily ended. A sleeping person or animal can be awakened quickly by, for example, a loud noise or a bright flash of light. All human beings and many kinds of animals must have a certain amount of daily sleep at regular intervals. Snakes, like all reptiles, do sleep. They are capable of doing this quite soundly despite the fact that they have no moveable eyelids to cover their eyes.
Among the vertebrates (animals with backbones), only reptiles, birds, and mammals experience true sleep, with changes in brain wave patterns. Different species of reptiles, birds, and mammals have different sleep patterns. Some sleep for many short periods every day, but others sleep for one long period. Animals that are nocturnal (active at night) sleep during the daytime. Some mammals, such as cattle, can sleep standing up. The other two groups of vertebrates -- fish and amphibians -- have periods of what might be called sleep. During these periods, they become less aware than at other times of what is happening around them. But scientists have found no evidence of brain wave changes that suggest sleep among such animals.