His name is Mike Rutzen and in South Africa, where he lives, he's known simply as "The Sharkman."
What he has discovered about these predators will surprise you: far from being mindless killing machines, Rutzen believes great whites are smart, curious, and not out to kill humans. And as CNN's Anderson Cooper saw when he went to South Africa, Rutzen is willing to risk his life to prove it.
Full Segment: The Sharkman
Web Extra: Anderson Cooper & The Great White Shark
Web Extra: Are People Food to a Great White Shark?
Web Extra: Swimming with a Great White Shark
Web Extra: Great White Shark Takes the Bait
Rutzen and Cooper took a boat ride to look for a great white Rutzen could swim with.
That's right, swim with. Before he gets in the water, he needs to find a great white that is both calm and curious, a shark he refers to as a "player."
Asked what a "player" is, Rutzen told Cooper, "Well, a player is basically the shark that's so relaxed, has a nice personality, woke up on the right side of the reef, and...the animal's willing to interact with us, it's so curious."
Rutzen says great whites have personalities. They may be the top predator in the sea, but they are, he says, not the man-eating killers of our nightmares.
"Now how can you tell that's a player?" Cooper asked, looking at a nearby shark.
"Look how she's moving. She's checking everything out. Checking how slowly she's gonna do this. See how she looks at everything," Rutzen explained.
In Rutzen's mind, this shark was curious and a "player."
This shark and several others have been attracted to Rutzen's boat by chum, a mixture of bait and fish blood. It's believed great whites can smell a single drop of blood from a hundred yards away.
Now that he's found a player, Rutzen and his cameraman Morne Hardenberg suit up and prepare to do the unthinkable: plunge into bloody water with great white sharks all around.
"There's no universities to teach you what these animals' social dynamics are and social behavior is. And the only way to find that out is by getting into the water," Rutzen explained.
Immediately, a curious great white comes straight at Rutzen; his only protection, his camera. Rutzen has figured out that great whites don't like the feel of metal.
Good visibility is crucial. The sharks are constantly circling, and Rutzen has to continually turn around so they don't sneak up on him.
"They are extremely inquisitive creatures. I like to say they're like little kids in a toy store. And you just tell them, 'Don't touch. Observe.' They all touch," he told Cooper, laughing.
"Problem is when they get curious, they sometimes bite," Cooper pointed out.
"Yes," Rutzen acknowledged. "The animals are not trying to actively kill you. They're trying to outwit you. I mean, there's a difference. And you're trying to outwit them again."
"So there's a mental battle going on or a mental game being played between you and the shark?" Cooper asked.
"I believe so, yes," Rutzen replied.
"That seems like the ultimate test of putting your life on the line," Cooper remarked.
"I would like to think that it's the ultimate trust between the animal and myself," he replied.
Rutzen is not a scientist. He was born on a farm and knew nothing about sharks until 20 years ago, when he began working as a fisherman along the rugged coast near Cape Town. These waters are home to the world's highest concentration of great whites.
"This is the perfect hotspot in the world for great whites," Rutzen explained.
It's a perfect hotspot because it's an ideal feeding ground for great whites. It's not far from the southern tip of Africa, where the Atlantic and Indian Oceans meet. The water is rich in nutrients which attract whales, huge shoals of fish and seals, some 60,000 of them.
Seals are a prime target for great whites. Early one morning, Rutzen takes us to an area called "Shark Alley," a spot the seals pass through searching for food.
Cooper asked, "With all the fish in the sea, why are the great whites so interested in the seals?"
"The reason for that is the blubber. Marine mammals have a blubber layer and their blubber is extremely energy rich," Rutzen explained.
While explaining this, they sighted a very large great white on the hunt.