Generally a well-balanced Scottie dog should weigh from and a female from . It is about in height. The Scottish Terrier typically has a hard, wiry outer coat with a soft, dense undercoat. The coat should be trimmed and blended into the furnishings to give a distinct Scottish Terrier outline. The longer coat on the beard, legs and lower body may be slightly softer than the body coat but should not be or appear fluffy. The coat colours range from dark gray to jet black and brindle, a mix of black and brown. Scotties with wheaten (straw to nearly white) coats sometimes occur, and are similar in appearance to the Soft-Coated Wheaten Terrier or West Highland White Terrier. Scotties are territorial, alert, quick moving and feisty, perhaps even more so than other terrier breeds. The breed is known to be independent and self-assured, playful, intelligent, and has been nicknamed the 'Diehard' because of its rugged nature and endless determination. The "Diehard" nickname was originally given to it in the 19th century by George, the fourth Earl of Dumbarton. The Earl had a famous pack of Scottish Terriers, so brave that they were named “Diehards”. They were supposed to have inspired the name of his Regiment, The Royal Scots, "Dumbarton’s Diehards". Scotties, while being described as very loving, have also been described as stubborn. They are sometimes described as an aloof breed, although it has been noted that they tend to be very loyal to their family and are known to attach themselves to one or two people. It has been suggested that the Scottish Terrier can make a good watchdog due to its tendency to bark only when necessary and because it is typically reserved with strangers, although this is not always the case. They have been described as a fearless breed that may be aggressive around other dogs unless introduced at an early age. Scottish Terriers were originally bred to hunt and fight badgers. Therefore, the Scottie is prone to dig as well as chase small vermin, such as squirrels, rats, and mice. Two genetic health concerns seen in the breed are von Willebrand disease (vWD) and craniomandibular osteopathy (CMO); Scottie cramp, patellar luxation and cerebellar abiotrophy are also sometimes seen in this breed. Common eye conditions seen in a variety of breeds such as cataracts and glaucoma can appear in Scotties as they age.