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‘Shark’s Eye Lens’ Reveals Deep-Sea Sharks Actually Glow in the Dark


Sharks take on appearance of a child’s glow-in-the-dark toy at great depths.

Ever wonder how a deep-sea shark sees the world? The answer is, in a dramatically different way than humans.

Scientists researching bioluminescence in deep sea sharks have developed a special camera lens that reveals how catsharks appear to one another. Seen through human eyes, they are pretty boring and drab-brown, but seen through the “shark’s eye lens,” they actually appear bright green.

The appearance is actually similar to a child’s glow-in-the-dark toy.

Newsela reports the findings of American Museum of Natural History’s Ichthyology department recently reported their findings in a scientific journal. Not only do the sharks appear bright green to one another, but the colors become more vibrant the deeper in the ocean the sharks go.

Catsharks live some 2,000 feet below the ocean’s surface, so it’s little surprise if you’ve never heard of one before. Even few scientists study them. It was ichthyologist John Sparks and his team who discovered the catshark’s glowing abilities.

“We’ve already shown that catsharks are brightly fluorescent and this work takes that research a step further,” he said.

You may be wondering why the sharks glow. One theory is the sharks can use the glowing patterns to communicate. Scientists observed different deep sea sharks had differing bioluminescent color patterns based on species and sex.

But it also appears this ability comes simply so the sharks can see each other in the darkest depths of the ocean. Different wavelengths of color get absorbed the deeper in the ocean you go. The exception is blue wavelengths, which is why water appears that color.

But it also makes things more difficult to see, especially the deeper you go.

“Imagine being at a disco party with only blue lighting, so everything looks blue,” scientist David Gruber told National Geographic. “Suddenly someone jumps onto the dance floor with an outfit covered in patterned fluorescent paint that converts blue light into green. They would stand out like a sore thumb. That’s what these sharks are doing.”

The shark’s skin actually absorbs and converts the blue wavelengths into the green colors that are seen through the shark eye lens.

These light displays aren’t easy to discern for human eyes simply because we weren’t built to live in the darkness of the ocean’s depths. Using the shark eye camera, scientists were able to see things from a shark’s perspective for the first time.

Who would have thought? It makes you wonder what strange appearance other creatures on this earth might take on to one another as opposed to what we humans see.


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‘Shark’s Eye Lens’ Reveals Deep-Sea Sharks Actually Glow in the Dark