An oddly charming image of how elephant seals may sleep:
The monitors revealed that the seals periodically flip onto their backs and slip into slow, spiraling dives. The seals wobble as they drift down, and most of the time their bodies follow circular paths toward the bottom of the sea, said study co-author Russel Andrews…. “[They] resemble a leaf that has dropped from a tree branch and is falling toward the ground, fluttering from side to side,” he said [National Geographic]. It seems likely, the scientists say, that the seals catch a quick nap during these long drifts; in fact, once in a while they strike bottom without even noticing.I wonder if submarines feel an occasional thud from a falling seal.
One other thing I didn't know about them:
These marine mammals undertake epics migrations of thousands of miles, in which they might not return to land for as long at eight months.