File:Humpback whale Tail Sailing behaviour.webm

English: Hawaiian Islands Humpback Whale National Marine Sanctuary today released rare video showing a humpback whale with its tail out of the water, seemingly catching the wind like a sail. The video was filmed during recent field operations conducted by the Office of National Marine Sanctuaries' Collaborative Center for Unmanned Technologies.

In the video, a humpback mother and calf are observed swimming and diving in the sanctuary off Maui's leeward coast. At one point, the mother appears to be doing a headstand and drifting with her tail out of the water.

According to scientists, tail-sailing is fairly common among southern right whales but has rarely been observed or documented among humpbacks.

"We're not entirely sure why the whales do this," said Ed Lyman, resource protection specialist for Hawaiian Islands Humpback Whale National Marine Sanctuary. "But we think this could be another way for them to rest, nurse, or just try to stay cool. More observations will be needed to confirm this theory."

The video was captured last month by a team of whale scientists and marine mammal response managers organized by the Collaborative Center for Unmanned Technologies. The scientists were trying to determine if small, remotely piloted aircraft can be used for whale research and disentanglement efforts in the sanctuary.

More at: https://hawaiihumpbackwhale.noaa.gov/