Can never tell for sure, but big mature bucks will often make rubs higher on trees, and on bigger trees. As far as tracks, bigger tracks are usually bigger deer, and one that's 3 1/2 inches wide is generally considered to be a big buck. So if its print is as wide as a 30.06 cartridge you probably have a shooter. Not that it can't be a monstrous doe, but probably a big buck.