Watch: Grouper Slurps Down A Shark, Not A Typical Meal

A close-up of an Atlantic goliath grouper. A fish like the one above, was caught on video eating a shark. Photograph by Raul Touzon, National Geographic Creative

The Atlantic goliath grouper (Epinephelus itajara) isn’t the meanest or fastest fish on the reef. It has neither venomous barbs nor impressive fangs. But as its name suggests, the goliath grouper does do at least one thing of note: It gets big. Darn big.

And as the saying goes, big fish eat little fish.

Recently, that little fish was a four-foot shark unfortunate enough to find itself caught on a fisherman’s hook. In the video above, which was submitted to Reddit earlier this week by user “SuperCub,” and is on its way to receiving a million views, you’ll notice that one moment the shark is there, trying to free itself. The next it’s simply gone—fish-napped by a goliath with no more fuss than the flick of a caudal fin. (For more video, watch “Photographer Swims With Huge Goliath Groupers.”)

Though the Atlantic goliath grouper can grow up to 800 pounds (363 kilograms) and eight feet (2.4 meters) in length, it subsists almost entirely on smallish mud crabs. But it seems sometimes the goliath will sometimes make exceptions.

“From all available data, goliath grouper do not eat sharks,” said Dr. Matthew Craig, a National Geographic grantee and marine biologist at the University of San Diego in California. “That said, groupers in general are opportunistic feeders. If there is something that is an ‘easy’ meal that can fit in their mouths, they will go after it.”

Christopher Koenig, a biologist from Florida State University, confirms that groupers preying on sharks is unlikely under normal conditions. For one, goliaths don’t have the kind of teeth necessary for tearing through flesh.

“Goliath grouper teeth are small and recurved,” Koenig said. “They are designed to hold the fish within the mouth cavity, not to cut it in pieces. So, to say that it swallowed the shark ‘in just one bite’ implies that it could have taken more than one bite, but it can’t.”

Perhaps it would be accurate to label groupers as ambitious as well as opportunistic. Craig said he has seen groupers in aquariums misjudge the size of prey and gulp it down anyway: “The result is that the tail end of the fish sticks out of their mouths until the other end is digested and they can swallow it”

Craig thinks this is likely what happened in the viral video. Talk about your eyes being bigger than your stomach.

Giants At Risk

Thanks to their size, there aren’t many predators that can take down a full-grown grouper. That is, except for humans.

“Believe it or not groupers are one of the most sought after fishes in the world,” Craig said.

Game fisherman prize the goliaths because of their size and the fish stories earned by hauling one in. Others catch the fish for its meat, though research shows you’d do well to avoid eating one—large groupers are absolutely riddled with accumulated toxins like mercury. Either way, by the 1980s, grouper populations had crashed and the species was declared endangered.

While some fisherman say goliath groupers have bounced back since then and should be taken off the Endangered Species List, most conservationists agree that the slow-growing giants are still recovering. (For more on this issue, read “Big Fish.”)

The good news? At least we know one goliath out there will be going to bed with a full stomach.

Watch video of goliath groupers up close with photographer David Doubilet, who shot the images for a story on this fish in the July issue of National Geographic magazine.

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