This video was put together by Pepe Murrieta, a Naturalist Guide from Mexico who co founded Cabo Pulmo National Marine Park. He got me onto a marine biologist expedition to photograph and GPS-tag the whale sharks off the coast of La Paz, Baja California. He had an underwater camera and caught some footage of me swimming with a “juvenile” whale shark, which is “only” about 7 metres long and weighs in at “measly” 7 tonnes. Adults can be more than 12 metres long and weigh more than 20 tonnes. The marine biologists explained that they have visually catalogued 250 separate animals, and that they know a lot of them by name as they come back year after year. Some are easily recognized by the scars and “boat hits” they have sustained. There were at least 15 different animals in the bay during our expedition, and I swam with almost all of them. Their mouths looked so huge that I wondered if they could swallow a human by mistake. At one point, with a huge gaping whale shark mouth approaching from one side and a “flock” of sting rays behind me, I admit I hyperventilated a little. But I have to say that this was one of the highlights of my life. It is right up there with coming face to face with a silverback mountain gorilla in Uganda and staring down and Elephant in Botswana. How many opportunities are there to be a couple feet away from an animal this big? Just don’t call them whales around marine biologists. They are fish. The world’s largest.