The Bloodhound is a large scent hound, originally bred for hunting deer, wild boar, and since the Middle Ages for tracking people. Believed to be descended from hounds once kept at the Abbey of Saint-Hubert, Belgium, it is known to French speakers as the Chien de Saint-Hubert.
This breed is famed for its ability to discern human scent over great distances, even days later. Its extraordinarily keen sense of smell is combined with a strong and tenacious tracking instinct, producing the ideal scent hound, and it is used by police and law enforcement all over the world to track escaped prisoners, missing people, lost children, and lost pets.
Bloodhounds weigh from 36 to 72 kg (80 to 160 lbs).They are 58 to 69 cm (23 to 27 inches) tall at the withers. According to the AKC standard for the breed, larger dogs are preferred by conformation judges. Acceptable colors for bloodhounds are black, liver, tan, and red. Bloodhounds possess an unusually large skeletal structure with most of their weight concentrated in their bones, which are very thick for their length. The coat typical for a scenthound is hard and composed of fur alone, with no admixture of hair.
This breed is gentle, and is tireless when following a scent. Because of its strong tracking instinct, it can be willful and somewhat difficult to obedience train and handle on a leash. Bloodhounds have an affectionate and even-tempered nature with humans, making excellent family pets. However, like any pet, they require supervision when around small children.
Up to at least the seventeenth century bloodhounds were of all colours, but in modern times the colour range has become more restricted. The colours are usually listed as black and tan, liver and tan, and red. White is not uncommon on the chest, and sometimes appears on the feet. Genetically, the main types are determined by the action of two genes, found in many species. One produces an alternation between black and brown (liver). If a hound inherits the black allele (variant) from either parent, it has a black nose, eye rims and paw-pads, and if it has a saddle, it is black. The other allele suppresses black pigment and is recessive, so it must be inherited from both parents. It produces liver noses, eye rims, paw-pads, and saddles.
The second gene determines coat pattern. It can produce animals with no saddle (essentially all-tan, but called ‘red’ in bloodhounds); ones with saddle-marking; or ones largely covered with darker (black or liver) pigment, except for tan lips, eyebrows, forechest and lower legs. These last are sometimes referred to as ‘blanket’ or ‘full-coat’ types. In a pioneering study in 1969 Dennis Piper suggested 5 alleles in the pattern-marking gene, producing variants from the red or saddle-less hound through three different types of progressively greater saddle marking to the ‘blanket’ type. However, more modern study attributes the variation to 3 different alleles of the Agouti gene. Ay produces the non saddle-marked "red" hound, As produces saddle-marking, and at produces the blanket or full-coat hound. Of these Ay is dominant, and at is recessive to the others.
Compared to other purebred dogs, Bloodhounds suffer an unusually high rate of gastrointestinal ailments, with gastric dilatation volvulus (bloat) being the most common type of gastrointestinal problem. The breed also suffers an unusually high incidence of eye, skin, and ear ailments; thus these areas should be inspected frequently for signs of developing problems. Owners should be especially aware of the signs of bloat, which is both the most common illness and the leading cause of death of Bloodhounds. The thick coat gives the breed the tendency to overheat quickly.
Bloodhounds in a 2004 UK Kennel Club survey had a median longevity of 6.75 years, which makes them one of the shortest-lived of dog breeds. The oldest of the 82 deceased dogs in the survey died at the age of 12.1 years. Bloat took 34% of the animals, making it the most common cause of death in Bloodhounds. The second leading cause of death in the study was cancer, at 27%; this percentage is similar to other breeds, but the median age of death was unusually young (median of about 8 years). In a 2013 survey, the average age at death for 14 Bloodhounds was 8.25 years.