Researchers just discovered the first omnivorous shark species in the world.
Contrary to the vicious image associated with sharks, not all of them are meat lovers. In fact, it’s been discovered that some sharks are said to be happy with their vegetable diet. In a recent study conducted by U.S. marine researchers, they were able to confirm the first discovery of an omnivorous shark: the bonnethead shark.
The bonnethead shark is commonly found in the shallow waters of the Western Atlantic, Eastern Pacific, and the Gulf of Mexico. They are a close relative of the famous hammerhead shark.
However, while the bonnethead reportedly feasts on marine vegetation, it’s not really as vegetarian as Bruce in the 3D animated film Finding Nemo. This shark is only 60 percent vegetarian. The rest of its diet is composed of crabs, snail, shrimp, fishes, and other smaller aquatic animals.
“Until now, most people thought that seagrass consumption was incidental when these sharks were hunting for crabs, etc. that live in the seagrass beds,” Samantha Leigh, co-author of the study and a researcher of ecology and evolutionary biology at the University of California-Irvine, said.
According to the research study Leigh and her colleagues presented at the Society for Integrative and Comparative Biology‘s yearly meeting last January, they cited that the bonnethead shark is the “first species of shark ever to be shown to have an omnivorous digestive strategy.”
“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 their paper recently published in the journal Proceedings of the Royal Society B.
For three weeks, Leigh and her team conducted several lab trials, feeding the bonnethead sharks 90 percent seagrass and only 10 percent squid. From there, the researchers were able to analyze the number of nutrients the sharks were able to absorb and how much they excreted. Surprisingly, the experiment saw the initially thought carnivorous sharks gained weight from the seagrass-heavy diet.
“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,” Leigh noted.
At the moment, it is still unclear how the bonnetheads began their plant-based diet. However, the study suggests that they could potentially be other omnivorous sharks out there.