The Original Mountain Cur is trademarked by dewclaws and naturally bobbed tails. Not all of them have them, but they resemble the old time curs. Hunters love it when they are born with natural dewclaws and double dewclaws becuase it more closely matches foundation stock of the old time pioneer mountain cur. In a bench show at a hunt, if you have two final curs and one has natural bob tail and dews, it will supposedly get the ribbon everytime. But, bobtails and dewclaws don't tree squirrels and coons. My pup had his tail docked when he was a few days old, but I wouldn't have cared one way or another if it was bobbed or not. Beagles get bobbed sometimes I hear to protect their tails in the briars. They say a beagle's tail can get pretty bloodied up in the briars. Other than that, I don't know the reasons besides people liking it that way.