Do All Animals Sleep? And If So, How Do They Sleep?
Like humans, sleep is an important function for most animals. But not all animals sleep alike.
Some stand, some lie down. Some close their eyes, others don’t. Some dream, some do not.
The way each individual species sleeps varies greatly based primarily on available food supply (the more they eat, the more they sleep) as well as defense mechanisms (the safer they are, the more they sleep).
Scientists can’t actually prove that every animal sleeps, but they’re pretty sure animal kingdom dwellers do catch at least some Zs.
Let’s take a look at the many different ways animals sleep.
How Do Giraffes Sleep?
These guys may have their head in the clouds, but they’re not actually sleeping all that much. Giraffes don’t need as much sleep as other mammals.
According to Zoogoer, giraffes sleep for just five minutes at a time about six times a day, for a whopping 30 minutes of sleep.
Giraffes are prey animals -- they’re often hunted by other animals for food -- so it would be quite dangerous for them to lie down for a long night’s sleep.
According to the University of Michigan Museum of Zoology, giraffes sleep standing up ... with one eye open ... and both ears moving.
How Do Horses Sleep?
Horses get a fair bit of sleep while standing up. But they only get REM (rapid eye movement) sleep when they lie down.
Hold up, there’s more.
Horses don’t actually need all that much REM sleep, so you’d think they wouldn’t lie down that often. Wrong. They can often be found lying down wide awake simply because it feels good.
Adult horses sleep about three hours a day.
Foals (baby horses) spend about 12 hours a day sleeping. Until they're more than three months old, that is. As they grow, they sleep less and prefer resting on all fours rather than lying down.
How Do Cows Sleep?
Cows sleep standing up sometimes, but they do their deep sleeping lying down. When they’re standing, they’re just resting and can wake easily. Cow tipping isn’t as easy as it sounds. Plus it’s just plain rude, so don’t do it.
Studies show that adult cows sleep about 4 hours a day. And they doze in and out for another 8 hours a day.
It’s called polyphasic sleep, meaning they sleep in small intervals (10 minutes at a time) throughout a 24-hour period.
Seems cows are master micro nappers.
How Do Dolphins Sleep?
Dolphins, like humans, need to sleep about eight hours a day. But, unlike humans, their brain sleeps in shifts.
Dolphins nod off in what’s called unihemispheric slow-wave sleep. That means that one half of the brain goes to sleep while the other stays awake. The awake half of the brain keeps the dolphin breathing and makes long, non-stop migrations possible.
When dolphins are in the midst of a sleep shift, they often rest motionless at the surface of the water so they can breathe.
Sometimes they swim slowly while sleeping, especially in shallow water, where they rest on the seabed before rising to the surface to breathe.
How Do Elephants Sleep?
In captivity, elephants sleep 3 to 7 hours at night, lying down for 1 to 5 hours at a time and getting up to feed between naps.
In captivity, African and Asian elephants lie down to sleep, most often on their sides. They also take naps while standing, and can sometimes be seen leaning up against a tree for support while catching a few Zs.
Wild elephants, however, sleep standing up more often, only lying down to sleep for about one hour every 3 or 4 days.
How Do Squirrels Sleep?
Have you ever seen a sleeping squirrel? Probably not since most common squirrels sleep in nests, called dreys, high up in the treetops.
Dreys are very much like birds’ nests, built with twigs, leaves, grass, paper, and anything else they can find to make a cozy tree fort.
A squirrel spends as much as 60% of its day asleep. That’s about 15 hours.
Squirrels are diurnal, like us, which means they're awake during the day and asleep at night.
How Do Bears Sleep?
You may think bears are the ultimate sleepers. After all, they hibernate for long periods at a time. But hibernating through the winter isn’t the same as sleeping through the night. In fact, bears’ sleep patterns change every few months.
Hibernation occurs during the coldest three to five months of the year. Hibernation is a much more serious process than snuggling in for the night.
During hibernation, a bear’s heart rate and blood flow lowers, his body temperature drops about 10 degrees, and his metabolism slows to about half.
When they wake in the spring, they spend the next few months sleeping very little. Instead, they spend their time hunting for food to get their weight back up (they lose about 25% of their body weight during hibernation).
When summer comes, bears nap during the day and hunt at night. It’s a good life.
And when the leaves start to change, bears recognize it’s time to gear up for the long winter’s slumber yet again. No more time for lazing around, the bear needs to spend about 20 hours a day eating to build up his body weight for hibernation.
Whether hibernating through the winter or resting on a hot summer day, bears make their homes in dens, often found under rocks, in hollowed out trees or in brush piles.
Not All Animals Sleep Alike
That’s for sure! Every animal has its own sleep requirements, and for many different reasons, whether it’s safety, comfort or basic survival.
One thing we do know for sure is that humans need their creature comforts. And that means finding the perfect mattress, pillows and bedding.
We spend one third of our lives sleeping, so what are you waiting for?
It's nap time ... get the gear!