Scientists are reporting peculiar behavior among this season’s humpback whales. A recent video by NOAA's Hawaiian Islands Humpback Whale National Marine Sanctuary shows a female humpback standing upside down with her tail sticking out of the water, performing a sort of underwater headstand.
Sanctuary response coordinator Ed Lyman says the rare behavior has a name: tail-sailing. It’s fairly common among right whales in the southern hemisphere, but is rarely observed in humpbacks. So far they’ve seen this in four different whales off Maui and O‘ahu.
Lyman says another theory is thermal regulation. By extending the tail above water, a breeze could allow the whale to cool off. He also stressed that more observations are needed before scientists can reach any conclusions.