Published: Sun, September 09, 2018
Sci-tech | By April Francis

The first known omnivorous shark species has just been confirmed

The first known omnivorous shark species has just been confirmed

Scientists say they have identified the first known omnivorous shark species, with 60 per cent of its diet consisting of seagrass.

- About 4.9 million alone in the Atlantic and Gulf of Mexico coastal waters of the U.S. -combined with their eating habits suggest that we need to re-evaluate the role that bonnetheads play in seagrass meadows. A small hammerhead, which belongs to the sharks, in the absence of "meat" without any problems and eats plant food.

The discovery was made by a team of scientists led by ecologist and evolutionary biologist Samantha Leigh of the University of California, Irvine, who tracked down five bonnethead sharks and investigated their digestion.

As the seagrass took root, the researchers added sodium bicarbonate powder made with a specific carbon isotope to the water.

Initially, researchers knew of bonnethead sharks eating up the marine plant but "it has been assumed by most that this consumption was incidental and that it provided no nutritional value", says Leigh.

The researchers ran a series of tests to see how much of the plant matter was digested.

The coastal bonnethead shark, which was previously thought to be exclusively carnivorous, enjoys eating seagrass, with up to 60 per cent of their guts full of plant material.

"Remarkably, the bonnethead's digestibility of organic matter is comparable to juvenile green sea turtles", they authors write.

"Bonnetheads have a digestive system that is very similar to other closely-related species that are definitely strictly carnivorous, so the fact that they are acting like omnivores is truly remarkable!"

Scientists fed lab sharks with seagrass and saw they all gained weight and more than met their energetic demands.

Results showed high levels of the carbon isotope in the shark's blood and liver tissue, indicating the nutrients from the seagrass had been absorbed by the sharks.

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