Isla Mujeres one day whale shark extravaganza, with over 150 of them, snorkeling with the largest fish in the ocean. Whale Sharks (Rhiniodon Typus) are harmless sharks, not whales. Reaching over 50’ and over 27,000 lbs. Whale sharks are filter feeders and their favorite meal is plankton. In order to feed, they scoop these tiny plants and little animals with their colossal gaping mouths while swimming close to the water’s surface.