Anderson Cooper dives with Nile crocodiles

They're always dangerous and usually deadly. But as Anderson Cooper finds out, underwater, the man-eating Nile crocodile can look graceful, even beautiful. His story, in which he dives with these dangerous, despised reptiles and the scientists who study them, will be broadcast on 60 Minutes Sunday, March 24 at 7:00 p.m..

The Nile crocodile has been on Earth for millions of years -- it is one of nature's oldest living predators. It's the most deadly of all crocodile species, growing up to 20 feet long, and it's known to snatch people, wildlife and livestock from the water's edge. Dr. Adam Britton, an Australian zoologist, was shocked when he first learned that filmmakers Brad Bestelink and his wife, Andy Crawford, were diving with these predators. "When I first heard about this, my instant, immediate reaction was, "That sounds crazy,'" he tells Cooper.

"I describe crocodiles as Ferrari's, they're just extremely, finely-honed creatures...just perfectly adapted to do what they do...the smartest of all the reptiles," says Britton.

Britton has been studying crocodiles for more than 18 years. He is building a genetic database on the Nile crocodile to devise ways of protecting the animal. For years, the only way to study these creatures was to capture and subdue them long enough to take samples. But that's changed. These days he's diving with crocodiles too and does his research up-close, underwater.

Bestelink and Crawford can only dive with the crocodiles during the winter months, when the water is cold and the crocs are more subdued. But by observing them underwater, they've developed a unique appreciation for the predator. "They are dappled and gold and black and you see them as more timid I think," she says. "I never used to think they were beautiful, but this is a whole different view of them."

Cooper ventures with Bestelink and Crawford down into underwater caves where these crocodiles lurk. It's murky down there, and the first thing they're able to make out are a glowing row of white teeth.