Michael Phelps has been watching Shark Week for about as long as the rest of us have been watching him on TV.
The five-time Olympic champion, 32, says he became obsessed with sharks as a teenager.
"Shark Week was always during major competition," he says, noting how Discovery's annual rite of summer often airs during the year's biggest international meet. And when swimmers aren't at the pool, they're expected to be in their rooms, resting with their feet up. That usually involves a lot of TV.
"So between (pool) sessions, I was watching stuff about sharks and trying to learn more," he says. "That’s where my biggest nerdy side comes out, he says, "because I’m so infatuated with water and infatuated with sharks.”
But this year, instead of watching Shark Week from the Olympic Village, he's onscreen as part of the action.
As a kickoff to Discovery's annual weeklong event, he takes his mark Sunday (8 ET/PT) for a 100-meter, open-water time trial in Phelps vs. Shark: Great Gold vs. Great White, off the coast of Cape Town, South Africa.
He doesn't swim side by side (that's too dangerous), and won't divulge exactly how they were paired up. But he strapped on a monofin (a wide fin with pockets for both feet that provides a nice boost in speed) in an attempt to level the playing field.
"In a race, I think my fastest speed was about five or six miles per hour," Phelps says. With the monofin, he estimates he got up to "8 to 10, maybe 12. But for me, it actually gives me more of an appreciation for how fast (sharks) move through the water, especially at their size."
Displaying his shark-nerd bona fides, he says a great white can hit a burst speed of 25 mph. "A mako shark can swim (in the) mid-40s. That’s mind-blowing."
A week later, he'll help close out Shark Week 2017 with Shark School With Michael Phelps (July 30, 8 ET/PT), swimming up close with a 13-foot hammerhead in the Bahamas. But he wasn't content to do it from within the confines of a cage.
"After, like, three to five minutes," he recalls, "I came up and said, 'Guys, I'm going out. Just be ready for it, because I don't want to be contained in here. I want to be with them in their habitat.'"
At one point, he says, "I had the opportunity to lie on the ocean floor and have a massive, massive hammerhead swim within a foot of my face. I was so calm during that. I was on a speaker and there were a couple of expletives that came out my mouth because I was more excited" than worried.
In addition to the once-in-a-lifetime learning opportunity, Phelps wants to spread the message that "sharks really aren't out to eat us or come up and swallow us whole. That's something from Shark School that other people can take away and understand what to do and what not to do in open water."
Other intriguing Shark Week shows:
Shark Vortex (July 24, 8 ET/PT): When the Gulf Stream pushes warmer waters into New England each summer, it provides a bonanza for scientists and shark enthusiasts as 30 species appear. This special focuses on three of the smartest and fastest: makos, great whites and porbeagles.
Sharks and the City: New York (July 25, 10 ET/PT): Seals have returned to New York Harbor, which means their greatest predator, the great white shark, probably isn't far behind. Marine biologist Craig O’Connell ponders the implications.
Shark Swarm (July 27, 10 ET/PT): Dr. Tristan Guttridge, a senior scientist at the Bimini Shark Lab in the Bahamas, investigates "shark societies," in which different types of sharks gather around the world.
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