Elephant seals enter ‘sleep spiral’ during deep ocean dives

Elephant seals enter ‘sleep spiral’ during deep ocean dives

Subject: Environment

Section:  Species in news

Context: Northern elephant seals might be masters of multitasking in the animal kingdom because they’ve learned how to sleep and dive at the same time — all while avoiding predators.

More on the News:

• The elephant seals can spend seven or eight months on foraging trips in the North Pacific Ocean and travel for thousands of miles away from land, which led researchers to question how and where the marine mammals sleep in the high seas.
• A new study, involving seals fitted with caps similar to those worn by humans in sleep clinics, revealed that the seals sneak in short naps during deep dives while holding their breath.
• When the seals experience sleep paralysis as they enter rapid eye movement, or REM, sleep, they lose control of their posture and continue to spiral down in a corkscrew pattern. The researchers refer to this as a “sleep spiral.”
• The research marked the first time scientists recorded brain activity in free-ranging wild marine mammals, capturing data from 104 sleep dives.
• The 10-minute naps during these 30-minute dives help elephant seals get about two hours of sleep per day during foraging trips, as opposed to the 10 hours they catch while snoozing on the beach during breeding season.

Elephant Seal:

• Elephant seals are large marine mammals that belong to the family Phocidae, also known as “true seals.”
• There are two species of elephant seals, the northern elephant seal and the southern elephant seal, both of which are found in the Pacific Ocean.
• Northern Elephant Seals:
  • Northern elephant seals are found across the Pacific coast of the United States, Canada and Mexico.
  • They generally breed and give birth in California and Baja California. That too usually on offshore islands from December to March. They fast during mating season, losing perhaps a third of their body weight.
• Southern Elephant Seals:
  • Southern elephant seals are the largest of all seals. They live in sub-Antarctic and Antarctic waters that feature brutally cold conditions.
  • Southern elephant seals breed on land but spend their winters in the frigid Antarctic waters near the Antarctic pack ice.
• These seals are known for their large size, with adult males weighing up to 4,500 kg and reaching lengths of up to 6.5 meters.
• Elephant seals are known for their unique lifestyle, spending most of their lives at sea and only coming ashore for breeding and molting.
• They are known for their deep dives, with some individuals reaching depths of up to 2,000 meters and staying underwater for over two hours at a time.
• These seals play an important role in the marine ecosystem, as they are a key predator of squid and fish. Additionally, their nutrient-rich feces contribute to the growth of phytoplankton, which form the base of the marine food chain.