Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
I'm not a fan of this movie even though it has some really good cinematography, sound design, make-up, costumes, locations, and some good action scenes, too. But Mel Gibson co-wrote and directed it to be over-exaggerated and hyper-violent to the point that it is so unbelievable that I just can't take it seriously. The hero of the movie, Jaguar Paw, already wounded and starving, is shot by an arrow that completely passes through his body but he is still able to outrun, all day and night and the next day, a band of not-wounded warriors and a huge black jaguar, then jump over a waterfall, then crawls through a pit of quicksand, and is able to kill off all of his pursuers, one by one. Seriously!
The snake scene involves a group of warriors somewhere in Central America (based on people from the pre-Colombian Maya civilization) who abduct some men and women from their small forest village and take them to the city to sell as slaves or to be used as human sacrifices. One of the men, Jaguar Paw, escapes and runs from his captors. When they are chasing him in the forest, one of the men puts his hand down by a tree right next to a venomous snake. Instead of biting his hand, which any real snake would do, the snake leaps a ridiculous several feet up in the air to bite him on the neck. He yanks the snake off and throws it to the ground where another warrior whacks it with his war club and picks it up by the tail. They all realize that the man won't survive and will die a painful death so they tell him to cut his own throat and leave him alone to do it.
The first snake we see looks like a real live snake, complete with some injuries - and when it lunges you can see what look like real fangs. It might be a special effect, and if so, it's very believable - my congratulations to the special effects department if it is But then we see a fake snake body and a fake snake biting his neck, and getting yanked off his neck and thrown to the ground. The snake that is picked up looks like another good fake. Basically, the only problem I really have with the snake scene is the ridiculous length of the snake's strike and the neck-biting shot. Everything else is believable.