Sheep That dont need shearing

Hey Everyone
I have some questions! I was playing soccer with a good freind of mine and, for some odd reason we got on the topic of sheep, she said when she was little she had a sheep that did not need to be shorn in the spring or summer, and I said what, i had no idea what she was talking about. She said it just molted. Well any way here is my questions can they do that, and if so what breed. I would love all the help i can get. Thanks a bunch.....
Lynn