So the staunch environmentalist offered himself as dinner to an anaconda - and was swallowed alive, filming every moment.
Anacondas, the largest snakes in the world, typically suffocate their prey before ingesting it, making Rosolie's attempt all the more dangerous.
But Rosolie survived, and now people all around the world will have a chance to watch his harrowing journey into the stomach of the beast, starting Sunday night when the video airs in the United States on the Discovery Channel.
"Everybody on Earth knows that the rainforests are disappearing and most people can tell you how important they are, but still, not enough people are paying attention, not enough people realize this is such a problem."
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The American activist said he was proud to take on the adventure, even though the prospect of dying was hard to swallow.
To avoid suffocating, experts crafted Rosolie a specially designed carbon fiber suit, equipped with a breathing system - as well as with cameras and a system to communicate.
The next challenge was trying to find a snake in the Peruvian Amazon jungle.
"We spent 60 days out in the jungle, camping, hiking, looking through swamps every night," Rosolie said.
Eventually, they found a female snake, which at, six meters long, fit the bill.
"When I went up to the snake, it didn't try to eat me right away," Rosolie recounted.
The explorer was swallowed head first and spent more than an hour inside the giant snake, he said, adding that he kept in touch with his team the whole time.
After the US showing, "Eaten Alive" will air on December 10 in Finland, Denmark, Hungary, Poland and Sweden, and two days later in Australia, before being broadcast in other countries, including China and India.