What is the most common chronotype?

In Breus’s model it is the bear, at roughly 55% of people (Breus, 2026). In chronotype research, most people sit between the early and late ends of a near bell-shaped curve (Roenneberg et al., 2007).

Is a wolf the same as a night owl?

They describe a similar person. Breus says someone who is not a “morning person” is likely a wolf (Breus, 2026). Researchers use “owl” as an everyday word for people whose body clock runs later (Roenneberg et al., 2019).

Can you be two chronotypes at once?

Breus writes that chronotypes fall on a spectrum and some people land in gray areas between his four types (Breus, 2026). In research, chronotype is a clock time on one continuous scale, so there are no fixed borders to cross (Roenneberg et al., 2019).

Does your chronotype change as you get older?

On average, yes. Chronotypes are latest at around 19 and become earlier after that (Fischer et al., 2017).

Guide · Body clock

Bear, wolf, lion and dolphin chronotypes: what the research says

Bear, wolf, lion and dolphin are animal names for people who sleep and wake at different times. They come from sleep specialist Michael Breus. Chronotype research works with the same idea but measures it as a clock time on one scale.

LightOtter editorial team · reviewed against the sources below · 13 October 2026 · Who is behind it

The short answer

What are the bear, wolf, lion and dolphin chronotypes?

They are the four chronotypes in a model by sleep specialist Michael Breus. According to Breus, bears are about 55% of people and follow the sun, lions wake early, wolves often go to bed at midnight or later, and dolphins tend to be sensitive to light and noise while they sleep (Breus, 2026).

What is a bear chronotype?

According to Michael Breus, the bear is the most common type, at roughly 55% of people. Bears follow the sun: they wake up when it rises and wind down as it gets dark. He puts their most productive hours at 10 a.m. to 2 p.m. (Breus, 2026).

On his bear page, Breus gives an ideal wake-up time of around 7 a.m. and an ideal bedtime of 11 p.m. (Breus, 2024).

What is a wolf chronotype?

Breus describes wolves as people who are not “morning people”. He puts them at about 15% of the population. Wolves usually wake up later, feel most productive between 10 a.m. and 4 p.m. and get bursts of energy in the evening. Midnight or later is a common bedtime for them (Breus, 2026).

On his author profile, Breus lists his own chronotype as wolf (Breus, 2026).

What is a lion chronotype?

In Breus’s model, lions tend to wake up early, often around 5 a.m., and feel most energetic before noon. Their energy drops in the early afternoon, and they fall asleep no later than 10 p.m. He gives their share as roughly 15% of people (Breus, 2026).

What is a dolphin chronotype?

Breus names this type after dolphins in the wild, which stay alert while sleeping. People he calls dolphins tend to be sensitive to light and noise while they sleep. He sees their most productive window between 10 a.m. and 2 p.m. and calls this the hardest type to build a schedule around (Breus, 2026).

What is the rarest chronotype?

In Breus’s model it is the dolphin, at about 10% of people. Together, he writes, the four types cover 95% of the population. He also writes that chronotypes fall on a spectrum and some people land in gray areas between the four types (Breus, 2026).

The research below does not count animal types, so it has no rarest type. It describes a near bell-shaped curve, with extreme early and extreme late types at its two ends (Roenneberg et al., 2007).

How does chronotype research measure it?

Researchers describe chronotype as the timing of your body clock. Sleep and wake times form a near bell-shaped curve in a population: the most extreme early types wake up when the most extreme late types fall asleep (Roenneberg et al., 2007).

The Munich ChronoType Questionnaire (MCTQ) uses the midpoint between falling asleep and waking up on free days. More than 55,000 people had filled it in by 2007, and it was checked against another questionnaire, sleep logs and activity monitors (Roenneberg et al., 2007).

Its authors note that complex biological traits such as chronotype vary continuously between people. The MCTQ gives it as a clock time rather than a score that sorts people into types. Colors in their charts are arbitrary, because the midpoint is a continuous variable (Roenneberg et al., 2019).

Compare workday and free-day sleep with the social jet lag guide.

Do chronotypes change with age?

Yes, on average. In a US diary study with more than 50,000 people, chronotypes got later during the teenage years, were latest at around 19 and became earlier after that. Before 40, men were on average later types than women; after 40 it was the other way round (Fischer et al., 2017).

Light plays a part too. In an early survey, people who reported more time outdoors in daylight slept earlier, across all chronotypes (Roenneberg et al., 2003).

Read why early bird and night owl are two ends of one scale.

Breus’s animals and chronotype research side by side

The studies cited here describe chronotype as one continuous scale and do not use animal types. Breus also places chronotypes on a spectrum, with gray areas between his four types (Breus, 2026). His shares and clock times come from his own pages; the studies here do not test them.

The four animal types next to what chronotype studies measure
Breus type	What Breus says	What chronotype research measures
Bear	About 55% of people; follows the sun; wakes around 7 a.m., bedtime 11 p.m.	Sleep times form a near bell-shaped curve, with most people between the early and late ends (Roenneberg et al., 2007)
Lion	About 15% of people; often wakes around 5 a.m.; asleep by 10 p.m.	The early end of the same curve (Roenneberg et al., 2007)
Wolf	About 15% of people; wakes later; midnight or later is a common bedtime	The late end of the same curve; on average, chronotypes are latest at around 19 (Fischer et al., 2017)
Dolphin	About 10% of people; sensitive to light and noise while sleeping	The MCTQ uses the timing of sleep on free days, not how easily sleep is disturbed (Roenneberg et al., 2019)

Which chronotype am I?

Breus’s quiz asks about things such as your age, when you wake up and whether noise or light bother you while you sleep, and then assigns one of the four animals (Breus, 2026).

You can work out the measure researchers use without any animals. On free days, with no alarm, note when you fall asleep and when you wake up and take the time halfway between. Asleep at 1 a.m. and awake at 9 a.m. gives a midpoint of 5 a.m. This midpoint of sleep on free days is the measure behind the MCTQ (Roenneberg et al., 2019).

If you sleep much longer on free days to catch up, the midpoint moves later, so the MCTQ corrects for that catch-up sleep (Roenneberg et al., 2019).

Find your midpoint with the 2-minute chronotype quiz.

What this is not

Bear, wolf, lion and dolphin are labels from one sleep specialist’s model, and a quiz result is an estimate from your answers, not a measurement of your body clock. If you are tired for weeks no matter when you sleep, or your sleep makes everyday life hard, talk to a doctor. LightOtter is not affiliated with Michael Breus or The Sleep Doctor.