Hokkaido University clarifies that a seal will rest asleep while falling like fallen leaves during diving

The Kita Elephant Seal does not land during migration, and the time to stay on the water is short, but when are you resting? As a result of reproducing the diving behavior in three dimensions by the 3D data logger, it seems that as a result of the reproduction of the diving behavior, the seals are resting while dying slowly while drawing a spiral so that fallen leaves fall down,Hokkaido University Northern Biosphere Field Science CenterIt seems that the research group led by Mr. Yoko Mitani Assistant Professor became clear last year, attracting attention.

Details are as below.
(PDF file)Seal sleeps while falling like a fallen leaf Northern Biosphere Field Science Center Assistant Professor Yoko Mitani

Dolphins and sea lions can sleep while watching the surroundings by alternating half of the brains, but such brain function has not been reported in seals. Nevertheless, the Kintaro Seal does not land at all during the migration of 2 to 8 months, it is several minutes to stay on the water continuously, and it was a big mystery as to when he was resting That's right.

In order to elucidate the resting behavior of the seal, we attached a 3D data logger (3 axis acceleration · 3 axis geomagnetism · velocity · depth · temperature measurement) to immature individuals of Kita Elephant Seal, and the body axis angle and 3 dimensional diving It said that the route was reproduced.

Hokkaido University Northern Biosphere Field Science CenterNewsletter No.05 (March 2009)Actual pictures that were included in the PDF file. In 2000 survey at McMurdo Station in Antarctica, it seems that he is about to catch Weddell seal right now.


As a result, it seems that there seems to be a pattern in the seals that seems to fall down so that the fallen leaves fall like a large circle while swaying regularly on the supine side. In other words, in order to avoid predators, seals seem to be able to rest at a depth of more than 150 meters on their back and sleep at a depth of water without predators.

It is speculated that there were no images etc in the materials, but as a selfish image, is it like this?


Furthermore, even in the same marine mammal, there are dolphins and sea lions that make a hemisphere sleep and seals that perform global sleep, and the relationship between sleep evolution and diving behaviors is very interesting, so please use the data logger in the future It seems that the research he expected is able to further elucidate the mystery of marine life.