How do dolphins sleep?
Whenever we’re seeing dolphins, it’s usually them jumping or swimming actively during the daytime.
But what do they do at night?
Do they slow down and just chill with their blowhole out of the water?
Let’s dig a little deeper.
How Dolphins Sleep
Dolphins sleep very similarly to humans.
They go through periods of both REM and non-REM sleep, although they are likely able to become fully aware of their surroundings without moving at all.
When dolphins need to go into a deep sleep or stay in one place, they will swim slowly along the surface of the water while sleeping.
They will also often rest their chin on the water’s surface, which helps keep them stable and prevents them from drifting away.
The one major difference between a dolphin and human sleep is that dolphins only have a single “REM-like” stage, while humans have four.
Dolphins may not dream in the same way that humans do, but scientists believe they still experience some sort of mental activity during REM sleep.
Dolphins are one of the few animals known to sleep with one half of their brain at a time.
This so-called unihemispheric sleep probably helps them stay aware of their surroundings and protect themselves from predators.
When a dolphin falls asleep, it will drift slowly to the surface of the water and rest its head on one side.
The inactive side of its brain will then go into a deep sleep, while the other side remains awake and alert.
If a predator were to swim close by, the dolphin would instantly snap out of its sleep and swim away.
Scientists aren’t entirely sure why dolphins need to sleep with one half of their brain at a time, but there are a few possible explanations.
A Dolphin’s Unihemispheric Sleep
One theory is that unihemispheric sleep helps dolphins conserve energy.
Since they spend so much of their time swimming, it’s thought that sleeping with one half of their brain at a time saves them from wasting energy by constantly switching back and forth between asleep and awake.
Another possibility is that unihemispheric sleep allows dolphins to keep tabs on their surroundings while they rest.
By keeping one side of their brain active, dolphins can still hear and see what’s going on around them even when they’re technically asleep.
This may be especially important for animals that live in dangerous environments, like sharks or killer whales.
Whatever the reason, scientists are confident that dolphin sleep is very different from human sleep.
In fact, they may not even need as much sleep as we do!
Some scientists believe that they can go for up to two weeks without sleeping, although they usually only sleep for a few hours at a time.
So the next time you’re feeling sleepy, just think about how the dolphins are probably doing just fine without a good night’s rest!
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