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These Beautiful Creatures Spend Their Entire Lives in Darkness

From blind salamanders to glowing squid, a new book explores the incredible biodiversity found in places where the sun doesn’t shine.

Snipe eel, phantom anglerfish, cockatoo squid. Don’t feel bad if you’ve never heard of these creatures, because even the scientists who study such things hardly ever see them.

Everybody loves the Dumbo octopods, named for their resemblance to Disney’s cartoon elephant. Also known as flapjack octopuses, these deep-sea cephalopods have webbing between their arms. And those adorable ear flaps? They’re actually fins. [Photograph By Dante Fenolio]

“When people think of biodiversity, they think of big things like lions on the African savanna and polar bears in the Arctic,” says Danté Fenolio, a biologist at the San Antonio Zoo. “But in fact, the bulk of biodiversity is really small.”

Really small, and really well hidden.

Fenolio is the author of a new photo book called Life in the Dark that features tiny, bizarre creatures found in places where the sun never shines. He has taken photos of animals that live everywhere from deep-sea trenches to the subterranean networks beneath termite mounds.

Named for its resemblance to both a bird and an eel, the snipe eel inhabits tropical and subtropical oceans around the world. Backward-facing teeth help it catch and devour crustaceans such as prawns and sergestid shrimp. [Photograph By Dante Fenolio]

Even in relatively shallow rivers and lakes, Fenolio says, turbidity can churn up sediment in the water so much that sunlight can’t penetrate. That means creatures that live just a few feet below the surface might as well be living at the bottom of the ocean.

“They’ve got the pressure, they’ve got the cooler temperature, and it’s absolutely dark,” he says.

Living in the dark is nothing new for these species, of course, and each has found ways to live without any help from the sun.

Groundwater salamanders are so well adapted to life in the dark that skin has grown completely over their eyes. Shown here are two different species, the Texas blind salamander (bottom) and Georgia blind salamander (top). [Photograph By Dante Fenolio]

For instance, the firefly squid creates its own light with specialized cells called photophores, which help it avoid predators and attract mates. And some species, like the Texas blind salamander, hunt by sensing miniscule changes in water pressure. The amphibian has so little need for sight, its eyes are completely covered in skin.

But there’s something far more terrifying than any of the strange animals Fenolio has studied. And that’s the rate at which many of these ecosystems are changing, degrading, or disappearing altogether.

The cockatoo squid is a tiny, translucent invertebrate that can change shape at a moment’s notice. When threatened, it can pull its head and tentacles inside its mantle and puff up like an inflated balloon. [Photograph By Dante Fenolio]

“So many of the amazing field sites I have worked over the years are now gone,” he says. “It’s like losing an old friend every time one of the special places vanish.”

Whether you see these creatures as beautiful or bizarre, Fenolio hopes the book will help shine a light on all the fascinating animals that thrive in darkness as well as the many more out there waiting to be discovered.

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