When going up stairs, you will need to place your dogs feet one at a time and help it along. Going down stairs requires a firm grip on the collar and a very slow walk down. It will quickly learn the right behavior towards a smaller animal. Never leave your greyhound alone with your family cat until you are sure they get along. Actually, gray greyhounds are rare.
Greyhounds come in solids, from white to black, and in patches and in brindle coloring.
They are a very colorful breed. You can find a color chart here. They run up to 45 MPH and can hit top speed in 30 feet. A greyhound appreciates a brisk walk every day. They also enjoy a good run in a fenced area a couple of times a week.