Do animals sleep? They do. But they do not all sleep the same way. Some sleep a lot. Some sleep just a little.

A bat sleeps about 20 hours a day. It hangs upside down to sleep.

A male lion sleeps nearly 20 hours a day.

Dogs sleep many hours a day, too. Dogs and their kin often sleep a third of the day or more.

An elephant sleeps very little. It gets only about 2 to 3 hours of sleep a day.

A giraffe sleeps mostly at night. It also takes quick naps in the day.

A horse can doze while it stands up.

A sea otter wraps itself in kelp when it sleeps. The kelp keeps it from drifting away.

An elephant seal sleeps about 10 hours a day on the beach.

Fish need to rest, too. Some parrotfish sleep inside a bubble of clear mucus.

A hummingbird can go into a deep rest at night. It is called torpor. As of November 2026, scientists say that on a very cold night its body can use as much as 95 percent less energy.

Even a tiny fruit fly sleeps.

Words to know

• torpor: deep rest
• kelp: sea plant
• mucus: slimy goo
• doze: sleep lightly