Sharkcano?! There Are Sharks Living in a Volcano, for the Love of God
“Sharkcano” isn’t the latest trashy summer movie with bad special effects. It’s the very real phenomenon of sharks making a home in lava water, and now a Nat Geo special.
Hear the phrase “Sharkcano” and you understandably envision one of those trashy and outrageous movies in which washed-up stars face off against massive man-eating sharks, deadly tornadoes, and awful CGI.
As summer TV shark-related programming became more and more popular over the last decade, so too did the outlandishness—and the wholly unscientific, fictional nature—of the projects. Specifically with those Sharknado movies, which at their peak/nadir, depending on your point of view, had Ann Coulter, Anthony Weiner, David Hasselhoff, Jackie Collins, and Sugar Ray singer Mark McGrath star in them.
So while the title of National Geographic’s new special Sharkcano may be understandably titillating, it comes with a certain, conditioned expectation of cheesy effects and a total and complete lack of scientific basis. But no. Friends, the Sharkcano is real.
“Did you think you were sitting in for a quality sci-fi B-movie?” laughs Dr. Mike Heithaus, the marine ecologist who serves as host of Sharkcano, which premieres Tuesday on National Geographic.
He had the same thought. “Somebody actually brought this to me was like, ‘Well, what do you think about sharks in volcanoes?’ and, you know what, I had the same initial reaction,” he says. “But then when you start thinking about it, it really makes sense.”
As the Sharkcano special underlines in its booming, dramatic narration, teasing the money shot video of hammerheads swimming in orange-clouded, lava-filled waters, “These two fearsome forces of nature share a powerful connection.”
In 2015, National Geographic scientists including explorer Brennan Phillips discovered a phenomenon that they never predicted: two species of sharks living inside the crater of an underwater active volcano.
That volcano, Kavachi, is located 60 feet below the ocean’s surface near the Solomon Islands in the Pacific Ocean. On a trip to study the caldera, Phillips and his crew dropped a robotic camera into the crater. (Humans, you see, cannot physically survive traveling inside an active volcano themselves.)
When the footage revealed hammerheads and silky sharks swimming in the scalding, highly acidic waters, you could have bowled them over with a feather.
Nothing about the environment should seem habitable, let alone inviting to the creatures based on everything researchers knew. Thus the obvious question was raised: Except for haunting the nightmares of galeophobic drylanders, what the hell were the sharks doing there?
Sharkcano tracks Dr. Heithaus as he crosses the globe in an attempt to figure that out. “My reaction was probably as giddy and as ‘oh my God, that’s cool!’ as people who don’t study sharks for a living,” he says, recalling the first time he saw the Kavachi video. “It’s not something I ever thought about, and it just seems like with too much noise and it being too hot, they wouldn’t be there. But sure enough…”
The special starts with Dr. Heithaus exploring the waters near the island of Réunion off the coast of Madagascar, albeit only safely from a boat. The paradise is under siege by sharks. Swimming has been illegal there since 2013. Eleven people have been killed by sharks since 2011, and 13 more have lost limbs. That’s 24 shark attacks on an island with fewer people than San Francisco.
Scientists have spent years trying to understand the perfect storm of human behavior and natural causes that make the area such a hotbed of shark activity. But the Kavachi video plants the seeds of a new working theory: some sort of synergy between the area’s sharks and its churning, active volcano.
The baffling question underlying all of this research is why sharks would be attracted to volcanic waters. The answer, and the topic Heithuas travels to disparate parts of the world to study in Sharkcano, may be magnetism.
Scientists have long been examining the electrosensory capability of sharks, which is used to find prey but may also be used to track volcanic activity, potentially helping the animals navigate the earth’s surface as they migrate. The theory is twofold. Sharks might use the Earth’s magnetic fields to navigate, using volcanoes as food pit stops. But as they adapt and evolve to the changing ocean climate, they may also be starting to become attracted to the fiery warmth of Earth’s furnaces.
“The research also gives us a window in some of these places to how important sharks are for ecosystems,” Dr. Heithaus says. “Around these volcanoes you've got lots of sharks and you've got vibrant reefs. Ultimately a lot of the work that we're doing is trying to find ways to make sure that we have healthy shark populations and healthy coral reefs, and that those are able to provide the resources that the people that live in these areas need.”
Plus, there’s no telling what practical, human application could come of studying these magnetism theories and how sharks are managing to adapt to the lava-filled waters in volcanoes. It’s researching shark behavior, he points out, that led to the water suit technology that Olympic swimmers are employing.
And if you may have thought, if sharks are living in volcanoes, for the love of God what other extreme, vaguely terrifying places might they also be—well, you’re not the only one.
“The one that comes to mind right away is sharks living thousands and thousands of feet below, a mile underwater,” Dr. Heithaus says. “It doesn't get much more extreme than that. The water's super cold. Just think of the crushing pressure that is on top of your body to live down there.”
If you put a styrofoam cup on a line and sent it down to a depth of a few hundred meters, it would come back up maybe a tenth of the size, for example. Some of the sharks down there glow, in order to blend in with other organisms that create their own light. (Imagine swimming in pitch black waters and all of a sudden there’s a glowing shark the size of a great white staring back at you.)
“This is a group of fish that have been around for 400 million years, so they are super well adapted to their environments, including the extreme ones,” Dr. Heithaus says.
And as outrageous as this current extreme one may be—sharks in volcanoes will never cease to be flabbergasting—as a public-facing expert, he’s mostly tickled that it’s 100 percent real.
“Sticking to the facts is important because there are still many of us shark scientists who, whenever we go into an elementary classroom, still have to make the argument that, no, Megalodon is extinct. We know you saw it on TV. But, yeah, it's been a few billion years.”