Why Deep-Sea Creatures Glow

Most of the animals in the deep sea naturally emit light known as bioluminescence, a trait that presents many mysteries to scientists. Video.

The mysteries of why and how many animals in the deep sea emit light, known as bioluminescence, continue to puzzle scientists studying the evolution of this natural glow.

©  2010 National Geographic, video courtesy Edith Widder


Unedited Transcript

There is a lot that isn’t known about life in the deep sea.

And biologist Edith Widder says if you dive deep, “turn out the lights” and you’ll see even more that still needs to be explored and studied

While it’s rare for land-dwelling animals to do so, Widder estimates that up to 90-percent of animals living in the open ocean make light, known as bioluminescence. And it makes for some impressive displays for the human eye.

Jellyfish…… pelagic worms…. A black dragon fish… are just a few creatures of the deep that make light.

This display is from a deep-sea shrimp, spewing bioluminescent chemicals out of its mouth.

And these luminescent particles were released by a comb jelly.

These emissions and displays could be to ward of predators, find food, or attract mates.

Widder, founder of the Ocean Research & Conservation Association, writes about new understandings about bioluminescence, and how it evolved in the May 7th issue of Science magazine.