Rattlesnake - After Dark

Plenty of moonlight on this Outer Territories night hike to navigate the roads, paths and ancient wagon tracks. But a light is necessary because of the critters that come out after dark. A lame change from the standard of just enjoying the night without glares ... bu that was in another world.
Flashlights when not normally used also delivered another cheerful lesson preferably unlearned (See "The Spiders Are Watching"). But all worth it not to step on a toad ... the bigger ones seeming to just pretend to be a rock until too late if not for spotting 'em.
This Prairie Rattlesnake did not coil up in defense; did not rattle but its tail was unclear; appeared rough and may have been injured. Not like they are always obligated to warn. Suspect this one did not yet see me as a threat; aware of light but any movement glared out by the clearly-warmer dirt road thermal background.
As always: PR's non-aggressive natures are noted. Past surprise encounters mostly a HEY YOU rattle; hidden in grass or almost invisible due to coloration. Others not seen just flee. Doesn't mean it won't bite a minute later but point noted; not vicious human hunters so I don't dispatch unless no-option forced (1 only so far).
(Need to boil down as template for all snake videos BUT): despite low light, my eyes and keeping my distance, the TRIED AND TRUE QUICK ID for a (venomous) viper vs. (non-venonmous, mostly harmless) serpent held strong: ALL GOOD if smooth head and smooth tail (like the tapering warhead of an air-to-air missile). TRIANGULAR HEAD and "ROUGH," not-smooth tail (i.e. rattles whether or not you can discern individual "pods" or your idea of what they look like) means BACK AWAY! Key point here:

NO, I did not see a perfect textbook triangle shape to head. NO, I did not see anything like a rattle cluster. SOMETHING was up on that end. First mistook at head end seeing what LOOKED like a small string or thin stub vibrating, mistaken for its flicking tongue. (Which showed quick at other end and drew attention). I DID SEE with 100% confidence that the head was kinda bumpy? ?sure bigger than rest? NO MATTER SPECIFICS. It wasn't a smooth torpedo so that's enough. No worries about trying to work out exact shapes or subtle diffs; both damn obvious.
Whazzthis? Nat Geo? OK wrap up note: what was up with that tail? Shrug. May have been partially injured; torn or misshapen. May have been FINE but snake didn't go into defense mode; have faced them in active coiled defense mode with me as the target threat and some mix chilling rattles with even more menacing, silent fast vibrations. They are not obligated to do so and surprises may make it moot.
Top side lesson: was in fuzzy mood, recognized it and guess I was up, moving and alert enough by then to SEE it. I had just passed less than ?4 minutes before, reached my turnaround point and began heading back with mind going to dinner. 3rd time now I was supposed to be on high snake alert but learned different thanks to obvious rattling or, even with low light, an obvious large stick-like object at right angles to the road track. Enough for now. Careful out there!