Have You Ever Wondered What Sperm Whales Look Like When They Sleep?

Sperm whales, or cachalots, are the largest toothed whales and predators on the planet.

Captain Paul Watson has declared many times that he believes whales are much more intelligent than human beings.

For these intelligently gentle giants, sleeping is quite an art form.

Contrary to previous assumptions that all cetaceans rest one side of their brain at a time, researchers have discovered that sperm whales seem to enter a full period of sleep. Before falling asleep, some sperm whales have been documented performing gradual rhythmic dives and then nodding off while suspended vertical and motionless in the water

“Many mammals show species-typical sleeping behaviour, such as dogs circling before lying down, lending support to the idea that sperm whales sleep during these drift dives,” said study author Dr. Patrick Miller, a professor of biology at the University of St. Andrews in Scotland.

It is estimated that they spend about 7.1 percent of their life asleep, typically between the hours of 6 p.m. and midnight.

These periodic bouts of sleep (generally about 12 minutes long) are used like short cat naps throughout the day to revitalize their internal batteries–prompting the assumption that sperm whales are the least sleep-dependent mammals on Earth. Scientists have also found that whales exhibit signs of Rapid Eye Movement, or REM sleep, which is thought to be the dreaming phase in humans.

Aside from sleeping in strange positions and having the largest brain of any creature known to man, sperm whales’ heads are also filled with a peculiar substance called spermaceti. Though scientists have yet to understand its purpose, they believe the fluid, which hardens to wax when cold, may help the animal control its buoyancy. Sperm whales are known to dive to depths of 3,280 feet in search of food and can hold their breath for up to 90 minutes.

This video of sperm whales sleeping below is incredibly fascinating!

Images: Dr. Peter G. Allinson