Diver captures rare footage of snoozing humpback whale

Monday, October 13, 2014, 10:50 AM - If you're feeling drowsy after Thanksgiving dinner on this holiday Monday, know this: You'll never snooze as deeply as the humpback whale in the video above.

On a certainly level, people know whales have to sleep sometime, but it's still weird to see it in real life.

Underwater photographer Kieran Bown shot the footage earlier in 2014 during a research project in the Turks and Caicos Islands, and it was posted to YouTube on Friday. It's a short peek at a 20-minute clip Bown shot, that included the female whale waking up and coming to check out the divers.

"The whale was completely at peace in the water and remaining silent. We floated and observed getting a great look at the giant," Bown said, reported in the Telegraph.

It seems many whale species really do sleep vertically like that. Here's a shot of a pod of sperm whales captured on camera by a documentary crew:

Animal Planet says humpback whales have to voluntarily remember to breathe, and so only sleep by "shutting off" half their brain at different times, and that was assumed to be true of all cetaceans until quite recently.

In 2008, researchers from St. Andrew's University in the UK happened upon a sleeping pod of sperm whales, sleeping vertically and not reacting at all to the boat drifting through the area.

Those scientists said sperm whales, at least, do actually enter full sleep, but may do so for only seven per cent of their time.

WATCH: The divers in the video below scramble out of the water pretty fast when that humpback whale acts up.