Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
This is one of those bigger-than-life, lushly-colored Cinemascope westerns of the 1950's. Maybe it has a few too many lush strings in the soundtrack and everybody looks a bit too well made-up considering they have been camping outdoors for months, but nobody wanted to pay to see dirty unshaven cowboys in ragged clothing until the revisionist and spaghetti westerns of the next decade, so I can overlook all that as long as there's a good story and amazing scenery, and this movie has both - it was filmed in the beautiful red rock country of Oak Creek Canyon and Sedona in Arizona.
The rattlesnake cameo appears in the middle of the film when a young woman, one of the survivors of a wagon train heading to Tucson that was attacked by the Apaches, is hunting for edible plants. She bends down to pick something when she gets too close to a rattlesnake that strikes her and bites her. It's a reasonably believable situation so for once I won't complain about it. They even used a place-appropriate rattlesnake - a nice big black Arizona Black Rattlesnake. As an added rattlesnake bonus, we get some tips on how to react to a rattlesnake bite when Comanche Todd, a white man raised by Comanches played by Richard Widmark, yells at the woman for running and pumping the venom into her heart. Then when the man holding their only gun rides around looking for the snake and then shoots it, which we hear but don't see. Todd complains that "We got six bullets and that idiot uses up 3 on a stinkin' rattler you could kill with a stick." Wise advice that would benefit all those other movie cowboys who think shooting a snake makes them heroes instead of what they really are - pussys. That's right, you guys heard me, draw! (And when you do, I'll be running away as fast as I can.)