Surprising Discovery About The Bonnethead Shark

The first known omnivorous shark has been discovered by researchers at the University of California. Bonnethead sharks, previously thought to only eat meat, have been researched and shown to process seagrass as a huge part of their diet.

In National Geographic’s article “This Shark Eats Grass, and No One Knows Why,” Hannah Lang explains, “in order to be considered true omnivores, an animal must obtain nutritional value or energy from the plants they eat. Without knowing why bonnetheads are eating sea grass, it’s hard to know if this habit is purposeful, said Leigh, who is studying the shark’s digestive behavior.” Samantha Leigh is a Ph.D. candidate at the university and an explorer for National Geographic.

Researchers are still taking a lot into consideration as they study the “omnivorous” sharks. Differences in young sharks and adult sharks and their feeding habits all play a part in this discovery. Lang writes, “younger bonnethead sharks have been found to have more seagrass in their stomachs than adult bonnetheads, which could point to a learning curve as the sharks mature and understand how to feed without simultaneously eating seagrass.”

What studies do show is that the sharks process and digest a lot of seagrass, and to do so, they have the microbiome in their gut that does what omnivorous and herbivorous animal guts do.