certain other long-backed breeds. Hip dysplasia, though occasionally seen, is usually mild, and does not often result in lameness due to the breed's typically muscular build. Responsible breeders use OFA or PennHIP evaluations to ensure that their breeding stock's hips are healthy. Because they are front-heavy and achondroplastic, young Glens are particularly susceptible to growth plate injuries that can significantly affect the development of front leg bones. Owners are advised to discourage their Glens from jumping off sofas, chairs, and beds until at least a year of age and to consult a veterinarian at the first sign of limping. After the age of 12 months, Glens generally do best on a diet lower in protein than other breeds. Temperament and behavior Glen of Imaal terriers can be energetic and tenacious, but they tend to be more even-tempered, more easygoing, and less vocal than most other terriers. While they love activity, they are not demanding, and are happy to relax by their owner's side. Their bark is deep and authoritative, like that of a much larger dog, and they are said to be good watch dogs. The "Glen sit," in which the dog sits on its hind end and holds its entire body vertical, is a posture not commonly seen in other breeds. As terriers, Glens can have a stubborn streak, but they respond well to a firm hand and can withstand correction when necessary. They are intelligent, learn quickly, and socialize easily. They are typically fearless and loyal, and are superb with people, including children. However, some can be dog-aggressive, especially when provoked. By maturity, most Glens develop a robust prey drive and will readily go for vermin such as rats, so they need to be well-socialized with other animals when young—particularly with small household pets that they might mistake for quarry, such as cats and rabbits. Glens often do well at Earthdog trials, Barn Hunt, and in agility. Although not typically strong swimmers due to their short legs and dense body, some Glens can work in water, and others have been trained to herd and drive sheep and cattle. Relationship to other breeds Though the exact origin of the Glen of Imaal Terrier is lost to history, some say that the breed may be related to the Soft-Coated Wheaten Terrier, another Irish terrier breed (in fact, some sources claim all Irish terrier breeds to be derived from the Soft-Coated