Being non-venomous, aggression is it's only defense. Being so it rattles it's tail against any loose terrain which mimics the rattlesnakes behavior. It's called Mimicry. But besides the obvious facts that it looks nothing like a rattlesnake and isn't even the same color, it also has no visible fangs like the rattlesnake, no venom ducts under it's eyes like the rattlesnake, and since you didn't notice IT ALSO HAS NO RATTLE. So, NO, this is not a rattlesnake.