The Animal that Sleeps the Least

Written and verified by the lawyer Francisco María García

Last update: 22 December, 2022

Humans require eight hours of sleep in order to be healthy. However, in the animal world, sleeping is a need that can reach incredible extremes, but which animals sleep the least?

What animal sleeps the least?

Elephant

These giant mammals — shown in the picture above —  are at the top of the list of animals that sleep the least. A group of biologists investigated a herd of South African elephants to determine how much time they spend sleeping.

After constantly monitoring them, it was found that elephants sleep an average of two hours a day, during several periods throughout the day.

Their large size requires them to spend most of the day in search of food. Elephants need to eat around 300 kilograms of food a day, which leaves them very little time for rest.

Unlike humans, these mammals almost don’t have the REM sleep phase, which is necessary for our memory to develop. The study shows that they barely spend 5-10 seconds in the REM phase. This doesn’t mean that they don’t rest; even when they’re standing with their eyes open, they have time to relax.

The research was conducted on wild animals that constantly search for food and water while protecting themselves from predators. Elephants in captivity, sleep up to four hours a day because they don’t have to deal with any of these inconveniences. 

Giraffe

Giraffes are another animal that sleeps very little. They only spend two hours a day sleeping during short periods of time throughout the day.

In general, they sleep seven minutes while standing, but occionaly they briefly get some deep sleep. However, it’s very rare to see a giraffe asleep.

Horses, donkeys, and impalas

These animal’s legs are designed to support them while they sleep on their feet. In total, they sleep up to three hours a day during seven minute periods. Even though they only need a little time to sleep, they usually lie down to sleep soundly.

These animals take turns sleeping when they are in a group. That way, while some sleep, others stay alert. Those few hours of sleep provide them with the energy they’ll need for the rest of the day.

Their sleep pattern doesn’t change even when these animals are domesticated. As for impalas, the males almost never go to sleep because they watch over the safety of the herd.

Shark

Sharks and other large fish must be in constant motion to get oxygen to breathe. They get oxygen from the water that passes through their mouths and exits through the gills.

This need doesn’t allow them to sleep, but that doesn’t mean they don’t rest because they do have periods of lethargy. Experts say that sharks use underwater caves to rest and obtain oxygen, but this has rarely ever been seen.

Whales and dolphins

In reality, both whales and dolphins sleep, but in a completely different way from humans, mostly because they don’t close their eyes.

Cetaceans must be in continuous motion to be able to got to the surface and breathe. So, they are ablie to disconnect one hemisphere of the brain while keeping the other active. This is how they manage to rest.

These animals’ offspring have long sleep phases. They stay next to their mothers and are dragged by them. 

Sheep, goats, and cows

Sheep and cattle sleep an average of four hours a day, divided into short periods. The rest of the day is spent looking for food and digesting it, which takes almost eight hours. Like horses and donkeys, they take turns sleeping when they’re in groups. 

Ant

This insect sleeps one minute naps sevearl times a day, for a total of 4-5 hours. The queen ant rests twice as much, up to 9 hours a day.

The animals that sleep the longest are those that must stay in motion to stay alive. Whether to escape threat, to breathe or eat, the previously mentioned animals are those that spend less time sleeping. That doesn’t mean they don’t rest. They only do it differently.