If your friend has a pet snake that always seems to be looking over at you, don't assume that you're dealing with an unusually curious reptile. The poor guy simply could be asleep a lot. When it comes to snakes, distinguishing between awake and asleep time isn't always so obvious.
Yes, Snakes Sleep
If you've never in your life seen a snake with his eyes closed, you're not alone. No one has ever actually seen that, because snakes just don't possess eyelids. Despite their not having eyelids, they can sleep just fine. Snakes' brains are in charge of their sleep. When they decide to turn in, they don't have to initiate the process by shutting their eyes.
In addition to serving the purpose of alerting others to sleep, humans' eyelids also function to protect the eyes from outside hazards. Although snakes don't have eyelids, it doesn't mean their eyes don't have any defense, however. Their eyes are equipped with transparent scales known as "spectacles." These layers not only keep snakes' eyes out of harm's way, they also stop them from becoming dry. Oddly enough, snakes shed these scales as they do the rest of their skin. If you ever look at a snake and notice his eyes taking on a hazy look, it might mean that he's on the verge of shedding.
Since you can't figure out whether or not a snake is sleeping by looking at his eyelids, you instead can look at him for any signs of motion. If a snake is totally still, there's a good chance he's catching up on some Zzzs. On the other hand, he could just be in relaxation mode.
Never get close to a snake out in the wild. Do not approach a snake just to figure out whether he's sleeping or not. Play it smart and be safe. Zoos make excellent places to look at snakes up close, sleeping or not.
Lizards and Eyelids
As fellow reptiles, lizards and snakes have a lot in common, notably that they're both cold-blood creatures. One major difference between the two groups sometimes involves the eyelids. Although snakes are free of eyelids, many lizards do, indeed, have them. Certain varieties of geckos, like snakes, are devoid of eyelids, however, and instead have spectacles. This makes it equally as tough to tell when they're asleep or awake.
- San Diego Zoo Animals: Snake
- City of Lawrence, Kansas: Got Snakes? Don't Panic
- Maryland Department of Natural Resources: All About Snakes in Maryland
- Snakes - Curiosities and Wonders of Serpent Life; Catherine Hooper Hopley
- The International Wildlife Museum: Savvy Senses
- Museum Victoria: Snake Eyes
- Toronto Zoo: Snake Biology
- Geckos - The Animal Answer Guide; Aaron M. Bauer