People typically sleep seven to eight hours in one stretch and stay awake for the rest of the day. Evolutionary scientists have assumed that this rhythm of sleep arose when our early ancestors went from being nocturnal to diurnal, but a new study of the Javan slow loris indicates that the human way of sleeping is much older.
Click here for original story, Slow loris study reveals human rhythm of sleep may be evolutionarily conserved
Source: Phys.org