Aah, the ocean ... an endless treasure trove of wonder. Each adventure in that "big blue" holds the sweet promise of new discovery. Most recently, for instance, we learned that great white sharks do this when they poop:

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While diving off the coast of Mexico's Guadalupe Island, the crew aboard the Nautilus Explorer witnessed great white shark celebrity "Lucy" releasing some majestic egesta. Underwater faecal tornadoes are something we've witnessed before, but this unique view allows us to see the full body spasm that's triggered when a mammoth shark like Lucy needs to lighten her load. 

It's worth noting that, should you find yourself in a similar situation (one for the proverbial bucket list?), screaming is not the best response, for obvious reasons.

We checked in with predator-prey ecologist Michelle Jewell, who's done extensive research on great whites, to find out more about the mouth-gaping manoeuvre you see in the video. While she admits she hasn't seen enough top-predator defecation to qualify as an "ordure oracle", she does offer a likely, and pretty simple, explanation.

"I reckon they open their mouths for the same reason we grin – the act of 'pushing' makes us do weird things with our faces," she explains. "Big sharks like Lucy have to make quite an up-down s-shape of their bodies to facilitate faeces flow, so perhaps the jaw opening up is just a spandrel of this body movement." 

That motion looks so out of character because unlike dolphins, which employ the classic "mermaid-style" stroke, sharks swim using lateral (side-to-side) tail movement.

So there you have it folks. Even for 16-foot (4.8 metre) great whites, successfully excreting waste can take a bit of effort.

A billowing cloud of shark poop can be a scientific gold mine, as it holds chemical clues about what the animal has been eating, its stress levels and even where it hails from. Because great white sharks are highly migratory, this information is invaluable, and tough to obtain. 

But shark poop isn't just exciting for scientists and divers. As you can see in the video below, fish and other marine life often feed on these green plumes. Upon exiting, top-predator waste still contains enough carbon to be a nutritious (albeit unsavoury) snack.

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Top header image: Megan Murray/Flickr