Male dogs are usually 71 to 76 cm (28 to 30 inches) tall at the withers and weigh around 29 to 36 kg (65 to 90 pounds). Females tend to be smaller with shoulder heights ranging from 68 to 71 cm (27 to 28 inches) and weights from 27 to 31 kg (50 to 75 pounds). Greyhounds have very short hair, which is easy to maintain. There are approximately thirty recognized color forms, of which variations of white, brindle, fawn, black, red, blue, and grey can appear uniquely or in combination.
Popularly, the breed's origin is believed to be traced to ancient Egypt, where a bas-relief depicting a smooth-coated Saluki (Persian Greyhound) or Sloughi was found in a tomb built in 4000 BC. Analyses of DNA reported in 2004, however, suggest that the Greyhound is not closely related to these breeds, but is a close relative to herding dogs.
Historically, these sight hounds have been used primarily for hunting in the open where their keen eyesight is a distinct advantage. It is believed that they (or at least similarly-named dogs) were introduced to England in the 5th and 6th centuries BC by the Celts during their invasions.
The name "greyhound" is generally believed to come from the Old English grighund. "Hund" is traced to the modern "hound", but the meaning of "grig" is undetermined, other than in reference to dogs in Old English and Norse. Its origin does not appear to have any common root with the modern word "grey" for colour, and indeed the Greyhound is seen with a wide variety of coats.
Until the early twentieth century, Greyhounds were principally bred and trained for coursing. During the early 1920s, modern Greyhound racing was introduced into the United States and introduced into United Kingdom and Ireland in 1926.
Due to the unique physiology and anatomy of greyhounds, a veterinarian who understands the issues relevant to the breed is generally needed when the dogs need treatment, particularly when anaesthesia is required. Greyhounds demonstrate unusual blood chemistry, which can be misread by veterinarians not familiar with the breed; this can result in an incorrect diagnosis. Greyhounds have much less fat than other dogs, and therefore can not metabolize anesthesia as quickly. A female may have an elevated risk of cancer if she was administered hormones during her racing career. Veterinary blood services often use greyhounds as universal blood donors.
Although Greyhounds are extremely fast dogs, they are not high-energy dogs. They are sprinters and do not require much exercise once they leave the track. Most are quiet, gentle animals. Greyhounds are often referred to as "Forty-five mile an hour couch potatoes."
Greyhounds make good pets because of their mild and affectionate character. They can get along well with children and family pets (often including cats). Greyhounds are generally loyal, tractable dogs with developed intellects. Their talents include sighting and hunting. They do not have undercoats and therefore are less likely to trigger people's dog allergies (Greyhounds are sometimes incorrectly referred to as "hypoallergenic"). Most Greyhounds that live as pets are adopted after they retire from racing.
Most companion Greyhounds are kept on a leash because their hunting background has instilled a strong desire to chase things. Greyhounds can live in an urban setting but require moderate exercise on a regular basis. They enjoy walking and running outside.
An adult Greyhound will stay healthy and happy with a daily walk of as little as 20 to 30 minutes. However, as Greyhounds have a body fat of around 16%, compared to an average of 25% in other Canines, over-doing their exercise can be detrimental to their health.