Puzzled scientists are trying to figure out what a giant shark native to the Arctic was doing in considerably warmer waters thousands of miles south of its frigid home.
Researchers from Florida International University and the Belize Fisheries Department recently discovered a Greenland shark, which typically lives in the freezing waters of the Arctic, in the tropical waters of the Caribbean Sea while working with local Belizean fishermen to tag tiger sharks, according to a press release from the university.
The shark was swimming near the Belize Barrier Reef, the second-longest barrier reef in the world, the scientists said. The discovery marks the first time a shark of its kind has been found in western Caribbean waters.
Devanshi Kasana, a marine biologist at FIU and a Ph.D. candidate in the university's Predator Ecology and Conservation lab, at first thought that what she was looking at was a sixgill shark, which is known to live in the deep waters off coral reefs.
"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 said in a statement.
Kasana then conferred with her adviser and other shark experts, texting a photo of the creature. The final determination was that it was "definitely" in the sleeper shark family due to its large size, and was most likely a Greenland shark or a hybrid between a Greenland shark and a Pacific sleeper shark, according to FIU.
It is unclear whether the researchers were able to tag the shark.
"This finding is so exciting because it suggests that these ancient predators are potentially roaming the world's oceans from pole to Equator, but staying very deep in tropical waters," Kasana, who is still in Belize, said in an emailed statement to ABC News. "It feels great to be a part of this and be a part of what could be the first step in protecting sleeper sharks in this region."
Little is known about the Greenland shark. The half-blind shark subsists by scavenging on polar bear carcasses and can live up to 250 and perhaps even 500 years, according to the National Oceanic and Atmospheric Administration, making them the longest-living vertebrate known to science.
Greenland sharks are also massive in size and can reach up to 23 feet long and weigh up to 1.5 tons, according to National Geographic.
"Because little is known about them, that means nothing can be definitively ruled out about the species," the scientists said. "Greenland sharks could be trolling the depths of the ocean all across the world."
Greenland sharks, or Somniosus microcephalus, are listed as a vulnerable species on the International Union for Conservation of Nature Red List of Threatened Species. The biggest threats they face are climate change and severe weather, which are causing their habitats to alter and shift, and fishing and harvesting.
Hakarl, fermented Greenland shark or other sleeper sharks, is a national dish of Iceland. Greenland shark meat is poisonous until it is dried and fermented over four or five months, and emits a strong odor and tastes of ammonia.
Kasana emphasized that the discovery of the Greenland shark was a joint effort among members of the Belizean shark fishing community, the Belize Fisheries Department and FIU researchers.
The Belizean government recently declared three atolls, including Glover's Reef where the Greenland shark was found, and the deeper waters around it as protected areas for sharks. This declaration will help keep animals, including undiscovered ones that may be roaming the waters around Glover's Reef, safe, Kasana said.
"Great discoveries and conservation can happen when fishermen, scientists and the government work together," said Beverly Wade, director of the Blue Bond and Finance Permanence Unit in the Office of the Prime Minister of Belize. "We can really enhance what we can do individually, while also doing some great conservation work and making fantastic discoveries, like this one."