Science

Plant-Eating Shark Changes How We See These Predators

Plant-Eating Shark
Image source: YouTube Video Screenshot

The discovery of the plant-eating shark has stunned and surprised scientists; even though this species of shark eats plants, it still likes to hunt. The shark is the smallest member of the hammerhead shark family.

Researchers from the University of California, Irvine and Florida International University studied the newly discovered omnivore shark and have now published their findings in the Proceedings of the Royal Society B journal.

“We were absolutely surprised to find that the bonnethead sharks were taking an omnivorous digestive strategy,” Samantha Leigh, a doctoral candidate at the University of California, Irvine and the study’s lead author, told Fox News.

According to Fox, the plant-eating shark was previously thought to be entirely carnivorous. Scientists thought the shark was feeding on small fish, crabs, shrimp and mollusks before consuming plants.

Nevertheless, scientists discovered that the shark will eat grass and other plants where seagrass is widely available, so it has plenty of greens in its diet. Still, scientists couldn’t fully understand how the sharks digest the nutrients they receive from plants. To discover that, scientists decided to feed captive bonnethead sharks a diet solely based on seagrass.

Researchers have already known for a long time that the Sphyrna tiburo eats large amounts of seagrass. However, they weren’t sure whether it also receives nutrients from the plants. However, this study reveals that seagrass can make up to 62% of the bonnethead’s diet.

“Until now, most people thought that seagrass consumption was incidental when these sharks were hunting for crabs, etc. that live in the seagrass beds,” told AFP.

In their paper, the researchers explained that these plant-eating sharks are capable of digesting seagrass pretty well.

“Bonnethead sharks are not only consuming copious amount of seagrass but they are actually capable of digesting and assimilating seagrass nutrients, making them clear omnivores,” the researchers wrote in the journal.

“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,” Leigh told Fox News.

Also in their research, the scientists note that the innards of the plant-eating shark are thought to mostly be digesting a diet rich in protein.

“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,’” Leigh told Fox News.

Before trying to make these plant-eating sharks total herbivores, scientists should also consider the environmental impact on the animal.

“In an ecological context, we also need to evaluate the role that this highly abundant shark plays in crucial and fragile seagrass meadow ecosystems so that we can be sure to effective manage these habitats,” she said.

There could be other shark species with a similar diet, but it’s also possible this plant-eating shark an exception.