A new study has found that elephant seals have to work very hard to stay fat. It's the most complete study of the feeding behavior*of northern elephant seals.
Scientists paid special attention to the female* elephant seals during difficult two-month trips, in the northeastern Pacific Ocan. Researchers studied 48female elephant seals from Afo Nuevo State Park in California as they traveled large ocean distances. Their trip was around 6, 000 kilometers.
Scientists based their findings on data collected in 2011 and 2018. They used three small devices*.
One device, attached*under the jaw, counted the number of times the seals fed and measured their depth. A second satellite-linked device，attached to the head，followed the seals' ocean movements. The third device was a "smart" video camera and another depth sensor. It was also attached to the head.
The seals were found to spend about 20 hours every day - and sometimes a full 24 hours – in continuous deep-diving to feed on fish. They fed 1, 000 to 2, 000 times daily to stay fat, necessary for warmth in the cold waters. They eat huge amounts of small fish, but it is difficult for them to catch enough small fish to meet the energy needs of their large bodies.
Taiki Adachi of the University of St Andrews in Scotland led the study, said about the female elephant seals:
"They keep diving, for long periods of time, with only a few minutes breathing at the surface. "Adachi noted that the seals do not come back to land for their two-month trip. "According to our record of foraging, their time for sleeping is less than 20 percent of the day, "he added.
Northern elephant seals give birth in California and Baja California, usually on offshore islands, from December to March. During their mating season, they do not eat. During this period they lose about a third of their body weight.
