Deep Sleepers – Northern Elephant Seals Sleep Far Beneath Ocean Floor

A latest research into the sleeping habits of northern elephant seals has discovered that the massive pinnipeds sleep for simply two hours a day – lower than virtually every other mammal – and that sleep takes place deep underwater, the place the seal is secure from predators reminiscent of sharks and killer whales.

Northern Elephant Seal Sleep Analysis

Researchers from Scripps Establishment of Oceanography and UC Santa Cruz monitored the seals’ diving actions by attaching neoprene caps to the animals’ heads with a detachable adhesive.

Utilizing these and different sensors, the staff have been capable of monitor quite a few facets of a seal’s dive, together with period, depth and stroke charge. Critically to the research, the sensors have been additionally capable of monitor the seal’s sleep state.

Northern Elephant Seals Fighting
Whereas at sea, northern elephant seals sleep for simply 2 hours a day. The species sometimes spends simply two months on land every year.

The researchers then mixed their very own knowledge with current knowledge drawn from over half 1,000,000 northern elephant seal dives compiled by the Costa lab at UC Santa Cruz.


The staff discovered that the northern elephant seal – whereas at sea* – sleeps for a mean of simply 2 hours per day. The one mammal identified to spend as little time sleeping is the African elephant.

* Elephant seals spend as much as ten months of the yr at sea, solely hauling out to mate, give beginning and molt (see under).

One other fascinating facet of the northern elephant seal’s sleep patterns is that sleep happens far under the floor.

That is presumably an anti-predation adaptation; whereas at or close to the floor, the seals are at their most weak from assaults by sharks and killer whales.

When the seals enter REM sleep, they cease swimming, flip upside-down, and regularly spin downwards. This means that, like ours, the seals’ motion turns into inhibited throughout this part of sleep.

Information reminiscent of that exposed by the research is necessary in constructing a whole image of the northern elephant seal’s habits, thereby serving to protect the inhabitants of this characterful ocean mammal.

The unique paper could be learn right here (article behind paywall).

Northern Elephant Seal

The northern elephant seal is the second-largest seal species; solely the carefully associated southern elephant seal is bigger. Male northern elephant seals can develop as much as 4-5 meters in size and weigh between 1,500 and a couple of,300 kg – that’s considerably heavier than a typical compact automotive.

Northern elephant seals are sometimes discovered within the japanese Pacific Ocean, starting from the Gulf of Alaska right down to Baja California in Mexico.

Through the breeding season, the seals migrate to pick out rookeries on offshore islands and sure mainland seashores.

A major rookery for the species is the Año Nuevo State Park in California, the place every winter they arrive ashore in giant numbers to mate and provides beginning.

Elephant seals are carnivorous and feed principally in deep ocean waters. Their food plan is numerous, consisting primarily of fish and squid, however it might probably additionally embody sharks and rays.

The seals are identified to forage at depths of round 300 to 600 meters, however they’re able to diving as much as 1500 meters deep and may stay submerged for greater than an hour, making them one of many deepest diving pinnipeds.

How Lengthy Do Northern Elephant Seals Spend At Sea?

Northern elephant seals spend nearly all of their life at sea, endeavor two prolonged open-ocean voyages every year between their breeding and molting intervals on land.

After the breeding season, they continue to be at sea for a mean of 2-3 months earlier than returning to shore for molting.

Following this, they embark on an extended post-molting migration that lasts 7-8 months for females and 4-5 months for males.

Men and women spend 80% and 90% of their lives within the ocean, respectively. This makes them one of the vital aquatic of all pinniped species, spending as much as 10 months of the yr within the ocean and demonstrating a rare capability for diving and long-distance migration.

Uncover Extra With Energetic Wild

Important animals web page: Animals

Uncover extra concerning the southern elephant seal: Southern Elephant Seal

Uncover extra ocean animals: Ocean Animals

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