Do Animals Nap? 5 Surprising Sleep Facts

1. Chinstrap penguins: a nap shorter than your yawn

In a 2023 study published in Science, researchers recorded the brain activity of chinstrap penguins nesting in Antarctica. The birds have to guard their eggs constantly from predators and from aggressive neighbours. Their solution: microsleeps. The penguins nodded off more than 10,000 times a day, with sleep bouts lasting only about four seconds on average. [1]

Added together, those tiny naps came to more than 11 hours of sleep for each brain hemisphere per day. The researchers conclude that the benefits of sleep may build up in very small portions. [1] Their imaginary calendar would need a very small font: nap, nest duty, nap, repeat.

2. Great frigatebirds: sleeping in mid-air

Frigatebirds can fly over the ocean for days without landing. Do they sleep while flying? Niels Rattenborg and colleagues attached small EEG recorders to great frigatebirds and followed them on flights of up to ten days. They found that the birds do sleep in flight, sometimes with one brain hemisphere at a time and sometimes with both. [2]

But they sleep very little: on average only about 0.7 hours, or 42 minutes, per day in the air. That is just 7.4% of the time they sleep on land. [2] It gives “airplane mode” a rather literal twist. The impressive part is the measurement: the researchers recorded brain activity instead of assuming that a long flight must include sleep.

3. Dolphins: half the brain takes a break

Whales and dolphins have to keep surfacing to breathe, even while resting. A review by Lyamin and colleagues describes how they solve this: with unihemispheric slow-wave sleep. One half of the brain sleeps while the other stays awake. The eye on the side of the awake hemisphere often stays open, and many species keep moving while sleeping. [3]

Even more surprising: in cetaceans, the dream-rich REM sleep that humans have every night has been found only in negligible amounts or not at all. [3] So a slowly swimming dolphin may actually be resting. Give it space instead of trying to get a reaction.

4. Giant pandas: lunch, lounge, repeat

According to the Smithsonian’s National Zoo, wild giant pandas commonly nap for two to four hours between feeding sessions. They may sleep on their belly, side or back, stretched out or curled up. [4]

There is a simple reason: bamboo is not very nutritious, so pandas spend much of the day eating and save energy in between. If pandas wrote an out-of-office message, “between bamboo appointments” would be a strong contender. Their long pauses are a panda fact, not a suggested length for your afternoon power nap.

5. Orangutans: a separate bed for the daytime snooze

Orangutans usually build a nest in the trees for the night. The Smithsonian’s National Zoo notes that they sometimes also nap in a simpler daytime nest. [5]

Apparently, the bedroom and the nap room can be different branches. For your own pause, a comfortable chair is a much more practical starting point than tree architecture. If you want to improve your own spot, read about a better nap environment.

Why animals sleep so differently

These examples show how flexible sleep is in nature. A penguin guarding its nest cannot afford long sleep, so it sleeps in seconds. A frigatebird over the ocean has nowhere to land, so it sleeps in flight, and very little. A dolphin needs to breathe, so only half its brain sleeps at a time. [1] [2] [3]

Each pattern is an adaptation to a particular life. Researchers study them partly to understand what sleep is for, and which parts of it can be split up, shortened or done with half a brain.

What animal naps can and cannot teach us

Humans cannot sleep with one hemisphere or bank 11 hours in four-second bursts. Seconds of sleep at a penguin nest, a panda’s long pause and a dolphin’s sleeping hemisphere are not interchangeable versions of a human 20-minute break. Nor does an animal’s ability to move while sleeping make drowsy driving safe for a person.

Some people try to “hack” their sleep with many short naps instead of one night. Research on humans does not support this; read why in our article on polyphasic sleep. Keep the curiosity, and leave the animal schedules to the animals.

Common questions about animal sleep

Do all animals sleep?

Most animals that have been studied show some form of sleep or rest, but it looks very different from species to species.

Can humans sleep with half their brain?

Not like dolphins. Humans normally sleep with both hemispheres at once.

Do animals nap too?

Some clearly do, like pandas between meals or orangutans in a daytime nest. [4] [5] To start your own, read what napping means.