Despite being almost exclusively marine-dwelling, sea turtles need to sleep. But how do they manage to do so underwater without drowning? Luckily, these fascinating creatures have a few tricks up their sleeve.
Marine/sea turtles are masters at conserving oxygen, and their metabolism slows down drastically when they’re sleeping. This helps them stay submerged for longer periods of time without having to surface to breathe. However, a quick inhale and exhale is still necessary to keep their lungs full of oxygen.
While they’re sleeping, a sea turtle’s heart rate and breathing slow down to the point that it is almost as low as when they’re awake. They can even stay underwater for months at a time! Known as “brumation,” this state of dormancy is similar to hibernation and allows sea turtles to conserve much needed energy. This is especially important for hatchlings and nesting females during the colder months and before they head out to sea for their own migrations.
Some species, such as mud and musk turtles, brumate during the day, while others, like loggerhead and green sea turtles, do so at night. Nocturnal turtles have poor night vision and hearing, which makes them more susceptible to prey and predators than other animals. Therefore, they sleep at night to avoid this risk. Typically, they sleep on the ocean floor or wedged under rocks and reefs to conceal themselves from their many natural predators.