Female Elephant Seal Spends 80% of Their Day Foraging Small Fish in Deep Seas

Male and female northern elephant seals have different foraging behavior. According to an article posted in the journal JSTOR. A male northern elephant seal would forage along the continental margin during the end of their migration while a female northern elephant seal forage in deep waters.

A recent study shows that the female northern elephant seal foraged small fish for up to 18 hours a day deep in the ocean.

Researchers from the National Institute of Polar Research, the University of California, Santa Cruz, and the University of North Carolina describes in their paper the foraging habits of female elephant seals which they recorded by attaching a camera and sensors to a captured specimen.

Their study, entitled "Forced into an ecological corner: Round-the-clock deep foraging on small prey by elephant seals," is published in the journal Science Advances.

What Do Northern Elephant Seals Eat?

Northern elephant seals are the largest of the true seals endemic to the Northern Hemisphere, wherein males could weigh up to 2,300 kg and females up to 90 kg.

Due to their large size, they need to eat a lot of food like squids, small fish, and small sharks. Since little is known about the foraging habits of females as they mostly spend their life on the open ocean, the team decided to learn more about what they do there.

According to the report of Phys.org, the team was able to capture several specimens and attached n infrared camera with built-in sensors and a GPS tracker on a female elephant seal. They also included a special device that cited the number of times the seal opened its mouth.

They found that the female elephant seal spends almost all of its time in the twilight zone, the transition part of the ocean about 200 to 1,000 meters below the surface.

The seals spend 80% of their day foraging for very small fish that are only two centimeters long deep in the ocean. The team also noted that the seals only slept for over an hour each day.

Elephant Seals Lifespan & Reproduction

According to NOAA Fisheries, pups are born between December to January in early winter while the breeding season happens from December to March. They have a gestation period of around 11 months.

Males and females have different lifespans with males only living for up to 13 years but females could live for up to 19 years.

They are polygynous breeders with a social hierarchy, wherein males form harems during their 9th or 10th year to battle for social status. They use their inflatable snout during the winter breeding season to resonate sound to vocally threaten other males.

O the other hand, females come ashore for a few days to give birth to a pup that was conceived from the last breeding season. Then they breed again before returning to the sea.

The study showed that female elephant seals could eat up to 2,000 fish each day enough to gain back the weight they lost when they fast during the mating season, wherein they lose 36% of their body weight as they shed their fur and patches of old skin that take about four to five weeks to complete.