Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
Five juvenile delinquents are let out of prison and sent to the Everglades to be rehabilitated through survival training taught by a Viet Nam war veteran named Indian Joe. One of them called "rattler" because he has a rattlesnake tattoo, runs away from camp one night. The next day, when Joe is tracking him, he falls down next to a rattlesnake. He tries to get up very slowly, but the snake bites him and he screams. For some crazy reason, he then picks up the snake. Indian Joe hears the scream, runs over to him, grabs the snake, and cuts its head off with a machete, throwing the head onto the ground. Indian Joe carries the snake and the now unconscious snake-bitten guy back to their camp, where he skins the snake and stretches the skin on a long stick. He probably used the snake meat for food, also, but we don't see that. One of the guys asks if he's dead. Joe tells him: "He took two hits. That's a lot of venom. I shot him up. He's got a 50/50 chance." Then he regains consciousness.
As far as I can tell, the live snake we see is an Eastern Diamond-backed Rattlesnake, the kind that lives in the Everglades. The snake Joe holds appears to be a fake snake prop, but the snake head and neck that we see thrown to the ground is that of a recently-decapitated live snake, because we can see it still moving. The guy who got bitten appears to be holding a real snake, so I assume they used a dead one for the scene.