Scientists discover first ever known omnivorous shark

In a first, scientists have discovered the first ever known omnivorous shark that feeds both on plants and other animals.

A team of researchers identified the first-ever omnivorous shark, the bonnethead shark which is also classified as the smallest relative of the hammerhead ones. The shark gets its nutrients from both seagrass and other sea creatures.

Publishing their study in Proceedings of the Royal Society B., the researchers wrote that the bonnetheads, found most in the tropical and subtropical waters along coasts of North America and the Gulf of Mexico, largely feast on crustaceans, clams, small fish, crabs, shrimps and octopuses, and were thought to be only carnivorous. However, they also like to eat abundant amounts of seagrass.

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Lead author Samantha Leigh told Fox News, “We have always thought of sharks as strict carnivores, but the bonnethead is throwing a wrench into that idea by digesting a fair amount of the seagrass that they consume.

“Given that bonnetheads have a digestive system that resembles that of closely-related species that we know to be strict carnivores, we need to re-think what it means to have a ‘carnivorous gut’.”

In order to further test the discovery, the researchers replanted seagrass and added to the water sodium bicarbonate powder made with a carbon isotope. Five bonnetheads were fed the replanted grass, along with squid for three weeks and the results showed that all of them gained weight, wrote New York Post.

The tests showed high levels of the isotope in the creature’s blood and liver tissue. The tests also demonstrated that the sharks digested the seagrass via enzymes that broke down the plants, such as starch and cellulose, as their razor-sharp teeth aren’t really suited for chewing.

The team found that these bonnetheads that can weigh up to 24 pounds and average 30-48 inches, were able to digest over half of the organic material in the seagrass.

Leigh said the astonishing results call for taking a closer look at other animals’ diets. “If other species are taking omnivorous digestive strategies as well, then we’d need to re­-evaluate their role as top predators.”