You've wondered about guys like Roger Munns whenever you're watching those big-budget nature documentaries. Who lives around schools of great white sharks for weeks, shooting film in close proximity to massive fish willing to snack on human entrails? What kind of men spend weeks underwater just hoping to get on film few minutes of turtles mating?

Munns takes those jobs. We caught up with him to find out about his work and why a horny whale is more dangerous than a hungry shark.

Munns is a partner in Scubazoo, a company specializing in underwater filming and photography based in Borneo. He rolled camera on such popular nature series as "Human Planet" (BBC/Discovery), "Saving Planet Earth" (BBC NHU) and "Life" for the BBC and Discovery.

Roger Munns shoots footage of hunting sword fish for Discovery Channel's 'Life.'"I've been lucky enough to dive in most types of environments, from freshwater lakes filled with sting-less jellyfish to kelp forests teeming with seals," Munns told us. "I've done the bulk of my diving on the rich tropical reefs of Southeast Asia where I live."

For "Life," Munns' claim to fame is risking life and limb to record humping humpback whales during their "heat run" in their native breeding grounds.

"These are not only some of the biggest mammals on Earth, but they are some of the biggest animals to have ever lived," Munns says. "To be in the water with just one of them is awe inspiring. To be in the water with between five and 10 whales, each around 500 times my weight, appearing out of the blue, heading toward me, was an interesting experience. In terms of size, you can liken it to standing on the freeway with 10 trucks bearing down on you."

Munns points out that whales might be among the biggest creatures ever, but they eat krill, one of the smallest. That eliminates the fear of becoming prey, but not the danger of being run down.

"People have been knocked out by fluke slaps in much more benign situations," he says. "We were essentially leapfrogging ahead of the whales in the boat, then trying to get directly in front of them. Once we were in the right place, I'd grab a deep breath and then fin down, looking all around me for the first sight of the whales. Once they appeared I had to steady myself and start shooting until they'd gone past. That would all happen in the space of 60 seconds -- the most intense experience I've had on water or land."

In fact, this underwater veteran said his sexy time with the whales was more dangerous than any run-in he ever had with sharks:

"Sharks get a very bad rap. I've dived with many different species of sharks -- including most of the ones which are considered dangerous like the great whites, tiger sharks and bull sharks. In the majority of those encounters, it's me trying to close the gap to get near the shark rather than the other way round. They are extremely sensitive and wary predators. More people are killed by toasters every year than by sharks."

Then again, we'd have no problem diving into the ocean to shoot a school of charging toasters.
Check out Munns' handiwork on the Discovery Channel series "Life," beginning this Sunday at 8 eastern and running for the next five weeks.