Deer rubs and rub lines tell you there is a buck in the area. When the deer loses its velvet, you'll start seeing rubs. It could be as simple as a hook in the brush or a rub on a tree. The purpose of rubbing is to strengthen a deer's neck for the upcoming breeding season. The size of the rub generally does indicate buck size. You can also tell about antler structure by looking carefully at the rub. Here on the high plains, you can find rubs on blue stem, sunflowers, fence posts, or windmill towers.