Sighthounds specialize in pursuing prey, keeping it in sight, and overpowering it by their great speed and agility. They must be able to quickly detect motion, so they have keen vision. They must be able to capture fast, agile prey such as deer and hare, so they have a very flexible back and long legs for a long stride, a deep chest to support an unusually (compared to other dogs) large heart, very efficient lungs for both anaerobic and aerobic sprints, and a lean, wiry body to keep their weight at a minimum.
The typical sighthound type also has a light, lean head, which is referred to as being dolichocephalic in its proportions. This shape can create the illusion that their heads are longer than usual. Wolves and other wild dogs are dolichocephalic, but most domesticated dogs have become brachycephalic (short-headed) due to artificial selection by humans over the course of 12,000 years. This change in head shape is closely associated with major neuroanatomical changes, but it is not clear whether these also lead to differences in behavior.
Dogs with different skull shapes may behave differently, but this is not entirely consistent. It has been suggested that brachycephaly may be a neotonic trait, i.e., a retention of juvenile traits, because dogs have been artificially selected for traits such as cuteness, intelligence, and ability to be domesticated, all of which are stronger in juvenile dogs. Brachycephalic breeds are not typically selected for scent work because of poor sense of smell. Dolichocephalic breeds have a wider field of vision but small overlap between the eyes, and therefore poor depth perception in most of their field of view.
Sighthounds such as the Saluki have existed for at least 5,000 years, with the earliest presumed sighthound remains appearing in the excavations of Sumer dated approximately 7000–6000 BC. The earliest description of a sighthound in European recorded history comes from Arrian's Cynegeticus, of the 2nd century AD. Although today most sighthounds are kept primarily as pets, they have been bred for thousands of years to detect movement, chase, capture, and kill prey primarily by speed. They thrive on physical activity. Some have mellow personalities, others are watchful or even hostile towards strangers, but the instinct to chase running animals remains strong.
Apart from coursing, open-field coursing, and hunting, various dog sports are practiced with purebred sighthounds, and sometimes with Lurchers and Longdogs. Such sports include racing, lure coursing, and other events