The name "starfish" is also used in a broader sense to include the closely related brittle stars. Starfish typically have 5 or more "arms" and usually hunt for shelled animals such as oysters & clams. They have two stomachs one of which is used for digestion, while the other can be extended outward to engulf & digest prey. Starfish are able to regenerate lost arms. A new starfish may even be regenerated from a single arm attached to a portion of the central disk.