Night owl (person)

A night owl, evening person or simply owl, is a person who tends to stay up until late at night.

The opposite of a night owl is an early bird, a lark as opposed to owl, someone who tends to begin sleeping at a time that is considered early and also wakes early. In several countries, early birds are called "A-people" and night owls are called "B-people." Researchers traditionally use the terms "morningness" and "eveningness" for the two chronotypes or diurnality and nocturnality in animal behavior.