Sleeping Giants: How Do Blue Whales Sleep?

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The thought of the largest animal to ever exist swimming peacefully through the deep blue ocean is one of the most comforting and soul-warming thoughts for ocean lovers like you and me.

Something about the image conveys feelings of serenity and joy. 

However, it’s important to keep in mind that moving a 150-ton body through the water consumes lots of energy from the blue whale, as does the digestion of the 16 tons of food this giant eats per day.

So how do blue whales replenish all this energy? By sleeping of course!

But now there is a very important question, how do blue whales sleep? They are mammals after all and need to come to the surface to breathe every now and then so that they don’t suffocate.

Let’s dive right in and see how much is known about the sleeping habits of these creatures.

How Do Blue Whales Sleep In The Water?

Unlike humans who are unconscious breathers and have no problem going into a state of deep sleep while still carrying on breathing as usual, whales and other cetaceans are conscious breathers who have to diligently decide to take a breath. 

As you can guess, sleeping underwater as a mammal is no easy endeavor but blue whales and other marine mammals have a very efficient system set in place and it can be split into 2 staple techniques:

1. Resting quietly in the water.
2. “Logging” is when one, or several blue whales are seen slowly swimming close to each other or floating on the surface.

There is a third method that is exclusive to mothers and calves and it is called “echelon” swimming. What takes place during this process is that the calf is placed very close to the mother’s mid-lateral flank and is therefore carried along in her slipstream.

So even though “echelon swimming” isn’t a process “made” for sleeping, blue whale calves will do it while engaged in this behavior.

This leads to the fact that mother whales will sleep while swimming for a short period of time after giving birth.

During the first few weeks after a calf is born, it doesn’t have enough fat or blubber to provide proper buoyancy and without the help of its mother slipstream, it would just sink to the bottom of the ocean.

Therefore it is of vital importance that the mother never stops moving.

As you can imagine, studying the sleep patterns of blue whales in the wild is quite difficult so a lot of information regarding the actual act of sleeping is taken from studies performed on captive bottlenosed dolphins.

Taking into account such studies leads us to assume that blue whales, and most cetaceans, sleep with half of their brain shut down and one eye open to sustain some awareness of their surroundings and to remember to breathe. 

How Often Do Blue Whales Sleep?

As I mentioned before, when it comes to the sleeping habits of marine mammals such as blue whales there are still way more unknowns than there is available information. How often they sleep still falls on the “unknown” area. 

What IS known, however, is that when it comes to how often different species of cetacean sleep it varies drastically from one to the other so it would be irresponsible to extrapolate data available for one marine mammal and make it a common assumption across the board.

What we can infer from studies done on similar whale species is that their daily sleep is split up into several different “naps” and it’s not taken all at once.

How Long Do Blue Whales Sleep?

This is a question that also falls more towards the “unknowns” of blue whale sleeping habits, but due to their biology scientists can assume that, like other closely related whale species, the blue whale can’t sleep for periods of more than 30 minutes at a time. 

The science backing up this claim is the fact that inactivity lowers body temperature and if a blue whale slept for longer than 30 minutes its temperature could reach dangerously low levels. 

It is important to note that the amount of sleep exhibited by cetaceans can be as much as 8 hours a day in some species and as little as 1.5 hours in others.

The amount of sleep seems to be related to its size, smaller cetaceans appear to sleep way more than larger species. 

What Positions Do Blue Whales Sleep?

Picture this, you are snorkeling or scuba diving in the ocean and everything is eerily quiet.

Suddenly, you realize you are surrounded by blue whales but they are completely still, suspended vertically at a 90-degree angle.

Seems like a scenario that is both dreamy and scary right? Well if it was to come true, then that means that you, my friend, have just stumbled upon a pod of sleeping blue whales!

They could even be at the same 90-degree angle but suspended upside down!

When sleeping vertically a pod will usually locate the calves towards the center of the formation to provide them better protection during this vulnerable state. 

Another common position is the one assumed by whales while “logging” which is simply staying still, or slowly floating on the water’s surface in a way that resembles a log. 

There are also reports of other cetacean species in captivity that will occasionally sink to the bottom of their tank and remain motionless.

Still, it is unknown if blue whales, or wild animals at all, display this behavior. 

Final Thoughts

I wish there was more information I could share with you regarding how the largest animal on earth sleeps but at the same time, I feel like part of the wonder and awe surrounding these beautiful creatures of the sea rests in not knowing every little thing about them.

Honestly, I think my biggest takeaway from learning about the sleep behavior of blue whales has been remembering that the ocean is a truly enormous place and a lot of its magic will forever remain a mystery to you and me. And you know what, I think there is such beauty in that.