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Belize - What's a shark ordinarily associated with the Arctic doing in Belize?

A half-blind shark that is typically thought to live in freezing Arctic waters, scavenge on polar bear carcasses and survive for hundreds of years, recently turned up in perhaps an unexpected place—a coral reef off Belize.

This marks the first time a shark of its kind has been found in western Caribbean waters off the world's second longest barrier reef.

Devanshi Kasana, a Ph.D. candidate in the Florida International University (FIU) Predator Ecology and Conservation lab, was working with local Belizean fishermen to tag tiger sharks when the discovery was made.

It had been a long night of fishing. By dawn, the weather had deteriorated. Storms were gathering on the horizon. The team did a last check of their lines. On the other end of one, wasn't a tiger shark, but a rather sluggish creature. It looked old—ancient, even—and more like an elongated, smooth stone that had sprung to life. It had a blunt snout and small pale bluish colored eyes. All together, these clues led scientists to think it was a member of the sleeper shark family.

"At first, I was sure it was something else, like a six gill shark that are well known from deep waters off coral reefs," Kasana said. "I knew it was something unusual and so did the fishers, who hadn't ever seen anything quite like it in all their combined years of fishing."

Kasana texted Demian Chapman—her Ph.D. advisor and Director of Sharks & Rays Conservation Research at Mote Marine Laboratory & Aquarium—to share the news. She also sent along a photo of the shark. Chapman's response caught her off guard. He said it wasn't a six gill. But, it looked a lot like a Greenland shark (Somniosus microcephalus).

After conferring with several Greenland shark experts, the final determination was it was definitely in the sleeper shark family—and because of its large size most likely a Greenland shark or a hybrid between the Greenland shark and Pacific sleeper shark (Somniosus pacificus).

Greenland sharks remain somewhat of an enigma to science. What is known about them is they tend to be seen in the frigid waters of the Arctic and North Atlantic oceans. The slow-moving species is also slow growing. Yet, a life in the slow lane may benefit them, because they have been estimated to live upward of 400 years—earning them the special designation of longest-living vertebrate known to science.

Because little is known about them, that means nothing can be definitively ruled out about the species. Greenland sharks could possibly be trolling the depths of the ocean all across the world. In fact, experts speculate that they could be found all over the world, living in tropics at greater depths, where they can find their preferred low temperatures.

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