Scenthound
This group is divided into two types: Tree Hounds and Trailing Hounds.

Tree Hounds: Included in this group are the six Coonhound breeds and the five Cur breeds. The Coonhounds are descended from Trailing Hounds brought to the United States shortly after the country was founded. The ancestors of the Coonhound breeds include the English Foxhound, red Irish hounds, the French Bleu de Gascogne hounds, and the German brindle Schweisshunds.

Hounds in America were utility dogs whose primary function was to help feed the family, but who also served as guard dogs and family companions. As the Tree Hounds evolved from the earlier Trailing Hound breeds, the dogs developed the ability to drive game up a tree, alert the hunter with a distinctive “bark,” and hold the game in the tree until the hunter arrived. Because of the vast size of American hunting grounds, the Tree Hounds needed superior stamina and a “cold” nose, that is, the ability to smell and track old, cold trails.

As more coon hunters became pleasure hunters and then competition hunters, the traits of the six individual Coonhound breeds became more distinct.

Curs were developed by early settlers in the southern and western United States as all-purpose dogs. Curs are excellent tree dogs, used to hunt squirrel, coon, mountain lion, and bear. They are used in Louisiana and Texas to hunt wild hogs. They also serve as stock dogs.

Trailing Hounds: The trailing Scenthounds are probably descended from Mastiffs bred by Celtic tribes in Europe and Britain. During the Middle Ages, Belgian monks developed a strain of black and tan hounds called the St. Hubert Hound, which was the basis of many of these breeds. Trailing Hounds are characterized by their strongly developed tracking ability, their hanging ears, their endurance, and their congenial dispositions which predispose them to working in a pack. Many Trailing Hounds are also famous for the baying sounds they make when hunting.

Source: United Kennel Club