Darkvision

Darkvision refers to the ability to see in the dark by allowing a creature to discern forms, as in normal daylight vision, only in shades of greys. It is similar to low-light vision, a trait more commonly found trait amongst some surface races. Underground creatures often have darkvision, including drow, illithids, and minotaurs.

Dx20070412iw drow1.jpg A drow Priestess usig darkvision