The grueling film production for Alejandro González Iárritu’s survivalist epic The Revenant was “a living hell,” according to a crew member. The cast and crew were subjected to scorching temperatures; the budget soared as a result of a worldwide hunt for snow; staff members abandoned the project; and some performers were allegedly dragged nude through the ice landscape in a 200-person combat scene. And now, Leonardo DiCaprio, has spoken up about the personal sacrifices he took in order to give the performance that might finally get him that elusive best-actor Oscar.

Leonardo DiCaprio claims he slept in animal carcasses, ate raw bison, and went for frequent swims in freezing rivers.

The filming included “some of the most difficult things I’ve ever had to do,” the actor told Yahoo Movies.

“I can name 30 or 40 sequences that were some of the most difficult things I’ve ever had to do,” he said. “Whether it’s going in and out of frozen rivers, or sleeping in animal carcasses, or what I ate on set. [I was] enduring freezing cold and possible hypothermia constantly.”

What did he eat on set?

“I certainly don’t eat raw bison liver on a regular basis. When you see the movie, you’ll see my reaction to it, because Alejandro kept it in. It says it all. It was an instinctive reaction.”

DiCaprio also talks about the difficult task of filming the brutal bear assault sequence, which required wires and careful choreography.

“[Those scenes]—amongst many other sequences—were some of the more difficult things I’ve ever had to do in my entire career,” DiCaprio says. “But the end result is going to be one of the most immersive experiences audiences will ever have with what it would be like to come face-to-face with an animal of that magnitude that is incredibly primal.”

The filming was said to be extremely challenging, with crew members departing at various times throughout.

“What we were trying to pull off was so incredibly ambitious, and [director Alejandro Gonzales] is vigilant and incredibly specific about what he wants up on screen, and he won’t accept anything less.

“So along the way, if we had departments that didn’t agree or departments that didn’t work correctly with the situation… I wasn’t privy to exactly what went on.”

For those unfamiliar with the plot, The Revenant follows a frontiersman (DiCaprio) who is on the lookout for the men who robbed him and left him for dead following a bear assault. The film is based on Michael Punke’s novel of the same name, which is based on a true story.

The Revenant, which also stars Tom Hardy, Will Poulter, and Domnhall Gleeson, will be released around the holidays.