I had a discussion with a friend on why my various farm-dogs love/d to roll in poo & carrion so much, and how it's an instinctive thing to mask their scent so they can sneak up on prey.

Afterwards I thought that is wasn't very bright of prey species to not question that dead things & manure seem mobile, and a quote from one of Larry Niven's books sprang to mind (I don't know if he was quoting someone else or not).