Cairn Terriers tend to look similar to a Norwich Terrier, but with some differences (for example the shaggy fur). Their outer layer of fur is shaggy, but they have a soft, downy undercoat. Their ideal weight is also 4.5-7.3 kg (10-16 lb), and the height 9–13 in (23–33 cm). Breeders, owners, and veterinarians have identified several health problems that are significant for Cairns. Some of these diseases are hereditary, and others occur as a result of nonspecific factors (e.g., infections, toxins, injuries, or advanced age).