Although Italian Greyhounds and Whippets have similar appearances, the largest physical difference between them is their size; the Italian Greyhound tops out at 15 inches and 18 pounds, while the Whippet can grow up to 22 inches and weigh 40 pounds. The Italian Greyhound is classified as a toy dog, while the Whippet is a hound. The Whippet has a high prey drive that must be controlled or channelled appropriately.
According to TheWhippet.net, the Italian Greyhound and the Whippet share ancestry, which accounts for the similarity in appearance. Modern Dog Magazine hypothesizes that the Italian Greyhound was originally bred to serve as both a companion animal and a small game hunter, while the Whippet started out strictly as a hunting breed. Despite this, the Whippet is also a very tactile and affectionate breed. The Italian Greyhound is more prone to barking than its Whippet companion. TheWhippet.net cites difficulties with house training as a primary reason for giving up an Italian Greyhound. Both breeds enjoy short bursts of activity, but the Whippet is more active overall during the day and more likely to engage in play. With supervision, the Whippet can be trusted with children, but the Italian Greyhound is too delicate for rough handling and play.