Australian researchers have discovered that whale sharks eat plants, making the iconic species the world's largest omnivores.
In a study published recently, a team from the Australian Institute of Marine Science (AIMS), Commonwealth Scientific and Industrial Research Organization (CSIRO) and University of Auckland discovered plant material makes up a portion of whale sharks' diet.
The team made the discovery while analyzing biopsy samples from the sharks at Ningaloo Reef in Western Australia (WA).
It makes whale sharks, which have been measured up to 18 meters long, the largest known omnivore species in the world.
Scientists analyzed samples of possible food sources at the reef, from tiny plankton to large seaweed.
They then compared the amino acids and fatty acids in the plankton and plant material to those in the whale sharks.
They found the shark tissue contained traces of sargassum, a brown seaweed.
"We think that over evolutionary time, whale sharks have evolved the ability to digest some of this Sargassum that's going into their guts," Mark Meekan, an AIMS fish biologist, said in a media release.
"So, the vision we have of whale sharks coming to Ningaloo just to feast on these little krill is only half the story. They're actually out there eating a fair amount of algae too."