I used to work for a vet and am now retired. Cairn Terriers can be aggressive. Even when they're shown the judge will have the handlers bring them all together and they will get up on their hind legs as to fight each other. When I was taking handling classes one attacked my 60 lb. male Chinese Shar-Pei in the neck. He was thrown out of class. I prefer the Soft-Coated Wheaton Terrier. They're much more laid back. they're a little larger and their coats take a lot more work though. But, for a larger Terrier once they're out of puppyhood they're very calm. Good-Luck with your research...
