Greyhound

Bred to hunt by sight and speed, with no reason to give tongue, and adoption groups consistently describe retired racers as dogs that bark only when excited or asking to go out. Most of the day goes on sleeping, often upside down. The one sound to know about is "rooing": a group howl, usually short, that greyhounds sometimes start together. One greyhound in a flat rarely has anyone to roo with, though a resident barker can teach it bad habits.