Sighthounds, also called gazehounds are a type of dog, that hunt primarily by sight and speed rather than by scent and endurance. They must be able to detect motion quickly, so they have really keen vision, these dogs specialise in pursuing prey, keeping it in sight and overpowering it with their great speed and agility.
Because, they are used to hunt and capture fast, agile prey such as deer and hare, Sighthounds have a very flexible back and long legs, giving a long fast stride. They have a deep chest, to support an unusually large heart (compared to other breeds), very efficient lungs for both anaerobic and aerobic sprints, and a lean wiry body, with weight kept down to a minimum.
Due to intentional selection for hunting by speed and sight, Sighthounds have unique anatomical and physiological features. Scientific studies have found hematology and serum biochemical profiles in Sighthounds, some of which were shared by all Sighthounds and some of which were unique to one individual breed.
Typically Sighthounds have a light, lean head which is dolichocephalic in proportion, this can create the illusion that their heads are larger than usual. Wolves and other wild dogs are dolichocephalic or mesaticephalic, but some domesticated dogs have become brachycephalic (short headed) due to artificial selection by humans over the course of the last 12 000 years.
Dolichocephalic dogs have a wider field of vision than brachycephalic dogs, but smaller overlap between the eyes and therefore possibly poorer depth perception in their field of view than brachycephalic dogs.
There is no scientific evidence to confirm the popular belief that Sighthounds have a higher visual acuity than other dogs. However dolichocephalic dogs, thanks to a higher number of retinal ganglion cells in their visual streak, retain a more heightened sensitivity than other dog types, to objects and rapid movement in their field of vision.
Sighthounds such as the Saluki/ Sloughi type (both named after the Selemeid empire), may have existed for at least 5 000 years, with the earliest Sighthound remains found, appearing in the excavations of Tell Brak dating back over 4 000 years ago.
Although today most Sighthounds are kept primarily as pets, some of them may have been bred for thousands of years to detect movement, to chase, capture and kill prey using their speed and agility. Some have mellow personalities, others are watchful and can be hostile towards strangers, they thrive on physical activity and their instinct to chase running animals remains strong.
Sighthound breeds include, the Greyhound, the Italian greyhound, the Saluki, the Afghan hound, the Irish Wolfhound, the Borzoi, the Scottish deer hound and the Whippet.
Scenthounds are a type of dog that primarily hunts by scent, rather than by sight. These dogs are generally regarded as having the most sensitive noses, they have large nasal cavities which help them to smell better, and typically have loose, moist lips which are said to help in trapping scent particles.
There are many breeds in the Scenthound group, and some Scenthounds may do other work as well, so exactly which breeds should be called Scenthounds can be a little bit controversial. Kennel clubs assign breeds of dogs to a group, and each Kennel club can determine which breeds it places in to any given group.
Most Scenthound breeds have deep booming voices, and use them actively when running, especially when following a scent. Although this can sometimes cause annoyance in settled areas, it is a valuable trait, which allows the dogs handlers to follow the dog or pack of dogs during the hunt, even when they are out of sight.
Scenthounds are not usually as fast as Sighthounds, they do not need to be, because they do not need to keep their prey in sight, but they do need endurance, so they can stick with a scent and follow it over different terrains. The best Sighthounds can follow a scent, even across running water, after several days.
A lot of Scenthounds hunt in packs of multiple dogs, long-legged hounds run quickly and require the hunters to follow on horseback, while short legged hounds allow the hunter to follow on foot.
The United kennel club in the U. S, divides the Scenthound group into two categories. The first, Tree hounds, includes the American hunting dogs known as Coonhounds and the European hounds from which they were developed. The second category is named Trailing Scenthounds, this includes dogs used for tracking of game, humans (as in search and rescue, and fugitive capture), they are also used for the detection of drugs and explosives.
Scenthound breeds include, the Beagle, the Dachshund, the Blood hound, the Foxhound, the American Foxhound, the Basset hound, the Kerry Beagle, and the Harrier.