Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
The Missing is a Western Fantasy directed by Ron Howard and starring Tommy Lee Jones, whose face is as chiseled and cracked as the rocky New Mexico Mountains where it was filmed, and Cate Blanchett. I call it a fantasy because it has a lot of magical Native American witchcraft that you have to accept if you want to believe the plot.
Samuel Jones (Tommy Lee Jones), who years previously abandoned his family to live as an Indian, and his estranged daughter Magdalena (Cate Blanchett) and her own young daughter are chasing a band of kidnappers who are mostly Apaches who have deserted from the US Army where they worked as guides. They kidnapped a bunch of girls, including Magdalena's older daughter, and are taking them to the border to sell to some Mexicans. Before the chase, we see Jones refusing a dinner plate of rabbit. He tells them he can't eat rabbit because he was bitten by a rattlesnake. Later we learn that an Indian medicine man told him that if he wore an amulet, said a prayer, ate no rabbit, and took care of his family for a year, then he would be cured, because a rattlesnake bite can make your soul very sick.
Then we see an eery night scene with several live rattlesnakes tied and hanging down from some branches and someone with black fingers milking a rattlesnake's fangs with the venom dropping down onto a human heart. Then he makes a snake inject its venom into the heart. He takes a large bird's foot, maybe that of an eagle, and stabs the claws into the heart. Then we see him sneak up on a man and punch the claws into his throat to kill him. It appears that he used the venom as part of his witchcraft to kill the man. It would have been much easier to use a knife, but that would be boring in a movie so we get to see some creepy rattlesnake witchcraft nonsense instead.
Jones' group comes upon the former camp of the witch and the others and the little girl falls to the ground screaming beneath a tree full of hanging rattlesnakes. Jones runs over but instead of shooting them he cuts the leather ties so the snakes can fall to the ground. He says something in his Indian language which the subtitles translate as "Go on now." This is a very rare example of kindness to rattlesnakes in a movie. Maybe it's part of Jones' rattlesnake bite cure. Regardless, one of the snakes strikes at him and he jumps back. (There must be a law that rattlesnakes have to strike at someone whenever they are used in a movie.) Jones tells them the man who used the snakes was a Brujo, a witch: "Snakes belong on the ground. This one hangs them in the air."
Most of the rattlesnakes are Western Diamond-backed Rattlesnakes, probably the most commonly used rattlesnake species in movies and perfectly appropriate for the New Mexico setting. The snakes we see hanging that Jones cuts down, however, are dead ones or props of some kind. No need to put the star in danger.