There are more differences than similarities between schnauzers and cairn terriers. They both have gray coats, and one of the schnauzer types is not much larger than the little cairn, but that's about it, as far as appearance goes. Both breeds have personalities that give them the potential to be great companions.
The schnauzer comes in three sizes: miniature, standard and giant. The standard schnauzer stands between 17.5 and 19.5 inches at the shoulder and weighs between 30 and 50 pounds. The giant schnauzer is quite a bit larger, reaching between 23.5 and 27.5 inches tall and weighing between 65 and 90 pounds. At the other end of the schnauzer scale is the miniature, running 12 to 14 inches tall and 11 to 20 pounds. The miniature schnauzer is still larger than the cairn terrier, who stands up to 10 inches at the shoulder and hovers around 14 pounds.
Get to Work
The American Kennel Club categorizes dogs according to groups. The cairn terrier is included in the terrier group and hails from Scotland, where his great hunting skills served to control vermin. All three sizes of schnauzers originate from Germany. The standard schnauzer, among the working group of dogs, is the original schnauzer, prized for his guarding and hunting abilities. The miniature schnauzer was created by breeding a standard schnauzer with affenpinschers and black poodles to create an excellent rat dog in a small size. The AKC considers the miniature schnauzer to be in the terrier group. The giant schnauzer, meanwhile, was developed to drive cattle to market and is also in the AKC's working group.
As a little dog, the cairn terrier tends to have a long life expectancy, around 14 or 15 years. This breed is generally health, but is prone to lysosomal storage disease, which is an enzyme deficiency. As well, the cairn terrier can be affected by the bone disorder Legg-Calvé-Perthes disease, which has a tendency to impact small breed dogs. The miniature schnauzer, with life expectancy between 12 and 14 years, are also vulnerable to Legg-Calvé-Perthes. Other conditions are eye problems, urine stones, comedone syndrome and the clotting defect known as Von Willebrand's disease. The standard schnauzer is prone to some of the same eye issues as the miniature schnauzer, as well as hypothyroidism, hip dysplasia, hemophilia and the heart condition pulmonic stenosis. The giant schnauzer is prone to hip dysplasia and eye problems, and is at risk of bloat. The standard schnauzer's life expectancy is similar to the cairn terrier's, at 13 to 15 years, while the giant schnauzer has a lifespan of 10 to 12 years.
A Difference in Personality
There is no guarantee a dog will behave a certain way, but breeds have traits they tend to remain true to. One thing the schnauzers and the cairn terrier have in common is intelligence. If you're looking for a smart dog, any of these breeds will satisfy you. In general, schnauzers tend to be loyal and territorial, making them good watchdogs, and they respond especially well to training. The cairn terrier and miniature schnauzer may be inclined to chase the family cat, given their vermin-hunting roots. The cairn terrier is especially good with children because he's so affectionate, durable and forgiving. He's also good at game play, such as fetch and hide-and-seek. If you'd like to try your hand at agility training, the schnauzers -- particularly the miniature and standard -- make great partners.