Up to 420 whale sharks gathered off the coast of the Yucatán Peninsula in Mexico, forming the world's largest known assembly of this species, according to a press release issued by the Smithsonian National Zoological Park.

The discovery counters the widely held belief that whale sharks, which can weigh more than 79,000 pounds, are solitary filter feeders that prefer to be alone in the open ocean. The impressive shark assembly proves they will gather for the right reasons. Food now appears to be the draw.

"Whale sharks are the largest species of fish in the world, yet they mostly feed on the smallest organisms in the ocean, such as zooplankton," Mike Maslanka, biologist at the Smithsonian Conservation Biology Institute and head of the Department of Nutrition Sciences, says in the press release. "Our research revealed that in this case, the hundreds of whale sharks had gathered to feed on dense patches of fish eggs."

Maslanka and his team identified the whale shark assembly using both surface and aerial surveys. Considering these sharks can grow to more than 40 feet long, the surface-level surveying must have been extraordinary.