Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
Four old west saloon prostitutes chased by Pinkerton detectives cross a river and stop to fix a wheel when a rattlesnake starts rattling and scares their horses into running away with the wagon. The wagon and horses are stopped on the shore of the river, but for some reason the snake suddenly got upset and started rattling. (Not very likely.) We never see the rattlesnake, not even a quick cutaway to a stock footage snake, but we know it's a rattlesnake because the rattling sound is loud enough to be heard in the next state and because when we see Cody Zamora, the leader of the group, aim her pistol and shoot, the rattling stops. Maybe they didn't have the money to hire a real snake with all the associated wranglers and insurance payments. Or maybe they thought a live sake wasn't shocking enough, because that night when the women sit by a campfire, we see Cody skinning a rattlesnake and hanging it over the fire to cook it for dinner. Then it looks like she is preparing the skin to use it later. It looks like she had the good sense to pick up the snake after she shot it.