Researchers observing marine mammals in far northern seas seem to push out controlled streams of bubbles in order to stay afloat while at rest upright in the water.
A research group fitted sensors on several large mammals as part of efforts to study resting patterns in the wild without disturbance.
New findings suggest the oversized melon-shaped organs do not really disrupt stability while at rest.
A number of adult females have been seen floating inverted off the bottom of the ocean as a recovery method to save strength.
The position could also help cows feeding calves between feedings, members of the team point out.
That documented habit add to the limited record of cetacean idle states, researchers write.