"The 'average' human sleeps about 8 hours every day. That's one third of your life! In other words, you sleep for about 122 days every year. A 75 year old person would have spent a total of about 25 years asleep." "Sleep may have developed because of a need of animals to protect themselves. For example, some animals search for food and water during the day because it is easier to see when the sun is out. When it is dark, it is best for these animals to save energy, avoid getting eaten, and avoid falling off a cliff that they cannot see. It is interesting to note which animals sleep the most and which sleep the least [http://faculty.washington.edu/chudler/chasleep.html]. In general, animals that serve as food for other animals sleep the least." http://faculty.washington.edu/chudler/sleep.html i'm notoriously bad for wanting to do nothing but sleep when i'm tired, but sometimes i think about trying to not sleep as much. i want to experience as much as i can in my one life. i'm a big believer in evolution and i also believe that not everything is how it seems at first glance. IF this really is one major reason why we sleep, i really might try not to sleep as much. on average, if you cut your sleep in half from 8 to 4 hours a day, by age 75, you would have experienced 12.5 more years of "life" than someone sleeping 8 hours a day. i actually could probably fight my sleepiness if i knew sleep was a evolutionary device to protect me. THINK ABOUT IT, IF SLEEPING KEPT CAVE MEN OUT OF TROUBLE, THE SLEEPIEST ONES WILL SURVIVE BEST. THEN WE EVENTUALLY END UP SLEEPY HUMANS, BUT NOW, MODERN MAN DOESN'T NEED ALL THIS SLEEP/PROTECTION (MAYBE)!