Night owl

A night owl, evening person, or simply owl, is a person who tends or prefers to be active late at night and into the early morning, and to sleep and wake up later than is considered normal; night owls often work or engage in recreational activities late into the night (in some cases, until around dawn), and sleep until relatively late in the day. People with delayed sleep phase syndrome are often described as night owls.

The opposite of a night owl is an early bird — a lark as opposed to an owl — which is someone who tends to begin sleeping at a time that is considered early and also wakes early. Researchers traditionally use the terms morningness and eveningness for the two chronotypes, or diurnality and nocturnality in animal behavior. In several countries, especially in Scandinavia, one who stays up late is called a B-person, in contrast to an early riser being called an A-person.

While staying up after dark was considered a negative trait, this changed in 17th and 18th century Europe (and subsequently spread beyond) due to the development and implementation of artificial lighting: more domestic lights, added street lighting, and adaptation by the royal and upper social classes. The introduction of chocolate, coffee and tea, and cafes that stayed open through dawn, became part of the new culture.

The term is derived from nocturnal habits of owls. Most owls sleep during the day and hunt for food at night.

Usually, people who are night owls stay awake past midnight, and extreme night owls may stay awake until just before or even after dawn.

Some night owls have a preference or habit for staying up late, or stay up to work the night shift. Night owls who work the day shift often have difficulties adapting to standard daytime working hours.

Night owls have often been blamed for unpunctuality or attitude problems. Employers, however, have begun to learn to increase productivity by respecting body clocks through flexible working hours, while the Danish "B-Society" of night owls and the American Start School Later movement advocate more school and workplace flexibility for the post-agricultural world.

Some research has found that night owls are more intelligent and creative and more likely to get high-paying jobs than larks, or morning persons. A study among 1,000 adolescents by the University of Madrid found that night owls scored higher than early birds on inductive reasoning tests, which often serve as a proxy for intelligence. However, they lag behind larks in academic performance, and they tend to have unhealthier eating habits, as well as higher rates of smoking. Some research suggests that night owls have a higher risk for bipolar disorder.