Docking is the removal of portions of an animal's tail. While docking and bobbing are more commonly used to refer to removal of the tail, the term cropping is used in reference to the ears. Tail docking occurs in one of two ways. The first involves constricting the blood supply to the tail with a rubber ligature for a few days until the tail falls off. The second involves the severance of the tail with surgical scissors or a scalpel. The length to which tails are docked varies by breed, and is often specified in the breed standard.