The Bonnethead Is the World’s First-Known Omnivorous Shark

Researchers found that these fish eat sea grass for nutrients.

One of a pair of new Bonnethead sharks at Chessington World of Adventures, Surrey.   (Photo by Steve Parsons/PA Images via Getty Images)
One of a pair of new Bonnethead sharks at Chessington World of Adventures, Surrey. (Photo by Steve Parsons/PA Images via Getty Images)
PA Images via Getty Images

Do sharks need to eat their greens too? New evidence suggests that the bonnethead shark is the world’s first-known omnivorous shark, according to an article in The New York Times.

The bonnethead is a smaller shark, often less than three feet in length. The traditional understanding of the animal is that it relies on small squid and crustaceans for its nutrients, but a 2007 study began to upend that interpretation when it found that up to 62 percent of a bonnethead’s stomach contents consisted of sea grass. University of California, Irvine researcher Samantha Leigh has expanded on that research, keeping bonnetheads in a large tank and feeding them a squid-wrapped roll of sea grass, of which the sea grass made up 90 percent.

The experiment found that bonnetheads get nutrition from sea grass the same way they do from meat, and on their grass-heavy diet, every shark in the test gained weight. More research is necessary to determine whether bonnethead sharks digest greens and receive their nutrients in a fashion similar to humans, but the bonnetheads’ taste for sea grass is sure to inspire more experiments about what sharks eat.

The InsideHook Newsletter.

News, advice and insights for the most interesting person in the room.