Sharks are not something you'd generally expect to find in an underwater volcano. And yet, a team of researchers who dropped a camera into the crater of Kavachi, an active, underwater volcano near the Solomon Islands, were surprised to discover that at least two species of sharks appear to live there.

In a video released by National Geographic, the surprise and excitement of the researchers is obvious.

“The idea of there being large animals, like sharks, hanging out and living inside the caldera of this volcano conflicts with what we know about Kavachi, which is that it erupts,” expedition leader Brennan Phillips said in the video. The waters in and around the volcano are very acidic, and very hot, increasing the sheer weirdness of the large animal life his team found there.

And yet, sharks live there. Hammerheads and silky sharks, to be precise. Phillips and his team, who were on an expedition funded by the National Geographic Society, also spotted jellyfish, a skate and other creatures living in the crater.

"One of the videos from inside the main caldera of Kavachi shows some jellyfish hanging out. They seem to be there naturally. And then we see some snappers and some small fish," Phillips told National Geographic, "and then sharks start coming after the camera. Sharks are cool in their own right — all of them are — but a hammerhead is particularly neat looking. And they're in there, in numbers, inside the volcano! Now I want to spend years trying to study that and why that is the case.”

When the volcano isn't actively "spewing hot lava, ash and steam," Phillips said, it's still pretty hard for humans to get close to it. "Divers who have gotten close to the outer edge of the volcano have had to back away because of how hot it is or because they were getting mild skin burns from the acid water.”

Among other things, the researchers are interested in knowing what happens to the sharks when the volcano erupts. "Do they get an early warning and escape the caldera before it gets explosive, or do they get trapped and perish in steam and lava?" Phillips wondered.

You can read more about the expedition at National Geographic.

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