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Where Do Whales Sleep?

A minke whale above the surface of the water

One question we are often asked is “Where do whales sleep?” While the answer to this seemingly simple question sounds innocent, it’s more in-depth answer is one that helps to provide the world a better understanding of the whale species as a whole. It goes without saying that whales sleep in the ocean, but the simple question of where they sleep also has many asking additional inquisitive follow-up questions like, do whales sleep underwater or above the water? Do they sleep while swimming or do they sleep while at rest? What else is happening within their body while they are nodded off and peacefully dreaming? When whales are sleeping, what predators lurk to find them and attack when they are not aware they are there but are aware of where whales do sleep.

“At night, when the sky is full of stars and the sea is still you get the wonderful sensation that you are floating in space.” ~ Natalie Wood

One fact we know for certain is that all whales of all species, including oceanic dolphins, sleep in the same place where they swim, eat, breed, give birth, play, and our personal favorite, where they interact with passengers. It’s no surprise that whales do sleep underwater and of course, in the ocean! We know most of you already knew this key fact but just in case you needed a reminder or are reading this information for the very first time, now you know. Since all whales and dolphins are mammals, ALL whales require air to breathe, just like us. Many of our passenger’s first thoughts when wondering where do whales sleep is followed by how whales take in oxygen while asleep. Unlike fish who use their gills to extract oxygen from the water, whales are required to take oxygen directly from the surface to breathe.

Their migrating behaviors also help us to understand their wake and sleep behaviors too. And, because these magnificent mammals travel for long extended distances, their body composition is created with the ability to hold their breath for astonishingly long periods of time. When we think about where do whales sleep, we have to direct our attention to species like the gray whale who travels up to 12,000 miles round trip to give birth to their young. Species with vast migration patterns who spend time in sub-zero degree waters, require the ability to slow down their heart rate to be able to rest throughout their long journey both to and from home.

Maybe you’re wondering if whales really do sleep underwater? Does the feeling of being weightless and the mere thought of floating in a pool or a bath while the water gently caresses your face and body make you feel a little sleepy? How about just the mere thought of what it feels like to feel the gentle rock and rock of the ocean? Well, that is what it is like for a whale too. If you are like many of our passengers and are pondering where do whales sleep, you may also be pondering when a whale’s 24 hour sleep cycle begins and ends. All animals within the animal kingdom go through a repeated 24-hour cycle called the circadian cycle. Unlike most dolphins who often hunt for their prey at night, most whales can often sleep throughout the night. This does not mean that they go to bed to catch some needed zzz’s at 10 pm every night after watching their favorite Netflix show and then wake up at 6 am to head off to work or school as land mammals typically do, but it does mean that they take extended breaks throughout the night to get some shut-eye and recharge to continue their migration and/or prepare for the next day of eating and nursing their young depending on the time of year. “Where do whales sleep” is not only an important question that, through answering it, helps us learn about whale behavior, it also furthers our knowledge about whale patterns as a species.

As we dig even farther into learning about a whale’s sleep behavior and question where do whales sleep, we also uncover their ability to be able to shut down half of their brain and allow for only one eye to remain closed while they are sleeping. It is believed that they do this so that they can maintain an awareness of the world around them, potential predators lurking in the distance waiting for an opportunity to strike, and most importantly, they can remember to continue to breathe.

“Consider the subtleness of the sea; how its most dreaded creatures glide under water, unapparent for the most part, and treacherously hidden beneath the loveliest tints of azure.” ― Herman Melville, Moby-Dick; or, The Whale

It is also important to note how long whales sleep when whales sleep underwater when looking to find out more about where do whales sleep. Most people think of a whale sleeping and think they lie horizontally in the water. What you may not realize is that their extra zzz’s can happen when they are either laying horizontally or vertically. Some sleeping can occur while swimming slowly next to one another or in a small group, or maybe even floating on the surface, called “logging”. One of the most famous photographs ever taken of a pack of sperm whales was photographed by a Swiss photographer Franco Banfi. His award-winning picture revealed a family pod sleeping vertically, highlighting the oldest females guarding the outskirts of the pod. An incredible documented moment of a truly amazing species. This same species has been known to sleep as deep as 10 meters below the surface and for only 7% of the time. Conversely, smaller beluga and gray whales sleep for 32% and 41% of the time, respectively while humpback whales will sleep for a maximum of only 30 minutes at a time.

 

Another fact we know for certain about where do whales sleep is the critical role their diet plays in this behavior. Since all whale behavior is predicated upon the characteristics of their prey, whales will sleep when the time to feed is less optimal. In some locations, studies have shown that krill perform a vertical migration at the approach of dusk. This food source is one of the most succulent food sources of both our largest visitors, the blue and fin whale. To paint this picture more easily in your mind, you can think of krill migrating as if they are lying side by side next to one another like sticks of gum in a package. Then, multiply those packs of gum (krill) into the trillions, which then grow into the “krillion”, a coined term thanks to our friends at Pixar. When we think of where do whales sleep, we must think of their proximity to the surface. As krill lie closer to the surface at night they are in turn, making it easier for these incredibly large baleen whales to feed on them during the later hours. If a whale’s prey is closer to the surface, this also means whales like blue whales and fin whales also take shorter dives to take in their massive 1-3 tons of krill needed each day to survive. A 2001 study conducted by Fisheries and Oceans Canada and GREMM, showed that at night when whales sleep underwater, blue whale dives are shorter and not as deep as those made during the day suggesting that this species of whale also could be taking periods of rest during the nocturnal hours.

“If we wipe out all of the fish, the oceans die. If the oceans die, we die.” ~ Paul Watson

Where do whales sleep is a question that also has us looking at a whale’s body temperature. A temp check? No, whales do not have COVID, but their temperature also plays a role in their overall sleep patterns. Lying motionless, humpback whales will rest at the water’s surface for a duration of up to 30 minutes but not much longer as they will lose too much of their body temperature when inactive if they sleep for longer periods of time.

Sadly, predators also spend their days and nights asking themselves where do whales sleep on a daily basis. A juvenile, solitary or sick whale is a copious supply of blubber and can keep sharks and other predators fed for weeks and even months (depending on the species) from a single whale’s blubber supply. A sleeping whale with an infant is a predator’s best friend.

In summary, when wondering where do whales sleep it is important to remember that every breath a whale takes is voluntary. If asked, do whales sleep underwater? The answer is simple, YES they do. Their bodies shut down but only half of their mind stays at rest so that they conscientiously remember to breathe. Breathing near the surface where whales sleep allows them to breathe more conscientiously, meaning each and every breath counts. This is likely why all sleeping whales and dolphins will sleep at the water’s surface. A whale’s respiratory system is vastly different from ours, so when it comes to sleep, a whale’s body enables them to stay underwater for several minutes without breathing oxygen. So, next time you are out with us on a whale watching trip and see a very slow-moving or inactive whale, you may just be witnessing a resting whale sleeping at or near the surface.

 

Until next time,

Capt. Dave’s Whale watching and Dolphin Safari

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