Tail of 2 horses

It was a sunny afternoon when Bob said to George,Hey, George, why don't we get ourselves 2 horses? We could ride them in the summer and in the winter we could put them in the paddock behind the house." George thought it was a great idea, so the next day they went out and bought themselves 2 horses. They rode them in the summer, but when winter came George got worried. He said "Hey, Bob, how are we going to tell them apart next spring?" Bob said, "Well, I'll shave the mane off mine and you shave the tail off yours." This satisfied George, so he did. The next spring when they went back to get their horses they found the horses' hair had all grown back. Alarmed, George said, "Oh great, now how are we going to tell them apart?" and Bob said, "Well, you can have the black one and I'll take the white one."