The waters at one of the world’s most active underwater volcanoes – the Kavachi volcano – is far too hot and too acidic for humans to even consider swimming in.

So you could imagine the surprise oceanographer Brennan Phillips and his colleagues received after dropping a robotic camera into the steamy waters only to find a number of hammerhead and silky sharks swimming and circling in the volcanic waters.

The site of the volcano is near the Solomon Islands, and the expedition was partly funded by National Geographic. After the camera crew dropped the camera down through the ash plume, it landed 55 metres below the surface in the crater, and recorded footage for the next hour.

After retrieval, the crew were excited after seeing a stingray on the film – which ended up being a little fish compared to the numerous hammerhead and silky sharks swimming around in the waters which are known to reach up to 400 degrees celcius during an eruption.

“The idea of their being large animals, like sharks, hanging out and living inside the volcano conflicts with what we know about Kavachi,” he told National Geographic. “When its erupting there is no way anything could live in there. “So to see large animals like this – that are living and could potentially die at any moment – it brings up lots of questions. “Do they leave? Do they have some sort of sign it’s about to erupt? Do they blow up sky high in little bits?”

Check out the cool video below: