As you may already know, whales are actually mammals – not fish. This has a few implications that make them stand out when compared to their other aquatic neighbors. First, whales are warm-blooded and give live births to their young ones (as opposed to laying eggs) and feed them milk. The most prominent distinction between whales and other fish is that whales don’t have gills, which means they cannot breathe the oxygen dissolved in water. Instead they have lungs which means they have to come to the surface every time they want to breathe air.
Although whales are mammals, they still obviously eat and sleep underwater. So, this brings up the question: how long can whales stay underwater before taking another breath?
Whales can hold their breath for a very long time, and this ranges species to species. The average whale can hold its breath for about 60 minutes. The Sperm whale can hold its breath longer than the average whale, for about 90 minutes. The whale that can hold its breath the longest, however, is the Curved Beak Whale, who can take long dives underwater for about 138 minutes! Compare this to dolphins who can also hold their breath underwater, but for a much shorter time period, around 3-5 minutes.
There are a few things that play in whales’ favor when it comes to holding their breath underwater. They have a very efficient respiratory system where their lungs can make the most out of each breath, giving them the ability to stay underwater for hours at a time. For perspective, humans breathe around 12-20 times per minute when resting, but only absorb 5% of the oxygen in a single breath. Compare this to a whale who can absorb as much as 90% of the oxygen in each breath. This means that a whale acquires much more oxygen than a human in a single breath to start with.
Whales’ lungs have the ability to store oxygen in a special protein found in muscles called myoglobin. They also conserve energy underwater by slowing their heart rate and limiting blood supply to only a few organs.
One of the biggest advantages whales have for holding their breath so long is myoglobin. Myoglobin is a protein present in the muscles of most mammals whose primary job is to bind to oxygen molecules which helps to store excess oxygen. Therefore, when you hold your breath even for a little while, myoglobin helps provide oxygen to your body. Since whales spend all of their time underwater, they have significantly more myoglobin than mammals on land.
The other remarkable advantage whales have when holding their breath underwater is their ability to conserve energy. When whales are underwater, they can slow their heart rate and limit supply to only a few organs at a time with no negative impact on their blood pressure. This gives them the ability to be highly efficient with their energy and get the most out of their breath.
If whales are mammals and need to breathe every hour in order to get oxygen, how exactly are they able to sleep?
Unlike humans whose breathing is involuntary while we sleep, whales’ breathing is voluntary. So, in order to sleep, whales (and dolphins) will engage in what is referred to as hemispheric sleep, where they shut down only half of the brain, and close the opposite eye. The other half of the brain that stays awake is at a low level of alertness in order to watch for predators to protect their young or other obstacles in the ocean. The alert half of the brain also helps the whale be conscious of the position of their blowhole to surface of the ocean in order to easily take a breath when it’s time. After usually two hours, whales will reverse the alert half of the brain so the other hemisphere can rest.
We are too! If you love whales as much as we do, we invite you to take an epic whale watching cruise with us at Harbor Breeze to see these majestic sea mammals up close and personal as well as other marine life. We have experienced naturalists on board each and every excursion so you can learn exciting facts about whales and their aquatic environment. Call us today for ticket information to book and unforgettable journey the entire family will love.