Gray Whale Sleeping Habits

Gray Whale Spouting

Gray whale observations by scientists searching for clues on gray whale sleep studied a rescued gray whale. For nine days they made continuous video-recordings and observations. They collected data on the whale’s behaviors, here’s what they found:

The gray whale rested in two ways: (1) by hanging just below the surface with its blowhole above water and (2) by laying on the bottom of the pool.

In both cases, the whale’s breathing slowed, its fins and tail moved slowly until it was fully resting, then the whale only moved to take breaths of air. When the whale rested on the bottom of the pool, it rose to the surface every few minutes to breathe.

At different times, the whale slept with both eyes open, both eyes shut, and just one eye open (indicating that only half its brain was active). The whale was more likely to be active during the day and resting or sleeping at night.

During sleep, the whale’s body sometimes jerked and twitched, in humans and other mammals, these movements indicate a deeper state of sleep and dreaming. Young gray whale calf’s actually rest, eat and sleep while their mother swims, towing them along in her slipstream, this is called echelon swimming. At times the mother will sleep on the move, in fact, she cannot stop swimming for the first several weeks of a newborn’s life. If she does for any length of time the calf will begin to sink, this is because the calf is not born with enough body fat or blubber to float easily.