This giant hound has 300 million scent receptors — more than any other breed. Bloodhounds can not only follow a scent on the ground, they can also air scent. Like their cousin the Basset, they are built to be the perfect tracking dog, with a large, long head; a nose with large, open nostrils; long ears that sweep the scent upward from the ground; and a cape of loose skin around the head and neck to trap and retain the scent. Last but not least, the Bloodhound’s stamina and persistence make him a superior trailing dog.
The scent of the person creates an “odor image" (a sort of smell photograph) in the dog's brain. The odor image is created from a variety of smells that a human cannot detect, including sweat, breath and skin. Although the world is full of smells, a bloodhound's sense of smell is so powerful that it can use the odor image to pick out the exact scent trail it needs.
Their signature wrinkly skin helps trap scents, too. Their long, droopy ears also act as scent sweepers, dragging the ground and sweeping scents toward their noses.