Sleepy seals

Do seals sleep in the water? YES! Read on to find out how these remarkable mammals doze off whilst staying afloat.

Australian fur seals have a fascinating way of sleeping while staying safe in the ocean. Unlike land mammals that experience full unconscious sleep, these marine animals use a special technique whereby one half of their brain sleeps at a time, while the other remains awake and alert to potential threats. This is called unihemispheric slow-wave sleep (USWS), also common in dolphins, whales, sea lions, as well as a number of birds.

While fur seals generally sleep on rocky outcrops, beaches or structures such as jetties and ramps, they do often take naps at sea. To rest, fur seals will float on the water’s surface with their noses out of their water, taking breaths at regular intervals.

They often hold one of their flippers in the air to help regulate body temperature, called the ‘sailing’ position. Another common sleep position is the “jug-handle” position, where the seal drapes one of its hind flippers over its back while keeping a front flipper raised. This helps them stay balanced and conserve energy while they rest. At times, they may also gently drift underwater before surfacing for air.

These unique sleeping adaptations allow fur seals to rest without becoming easy prey, ensuring they can maintain essential functions like swimming and breathing while still getting the sleep they need. For humans, that would be akin to sleeping while standing or walking!

Around Phillip Island you can often spot a sleepy seal float and rest in the water, usually around jetties (as in the above video), bridge pilons, and channel markers. Please do not disturb the seals while they are having their much needed rest. Observe from a safe distance and enjoy watching these fantastic creatures.

Join our cruises to learn more about seals and other amazing wildlife!