How do dogs follow trails so accurately?

Scenthounds, and particularly the bloodhound shown here, have a very highly developed sense of smell. This enables them to identify and respond to a tiny trace of scent, so that they can even locate buried objects. If it is hungry, a hound will be able to follow a trail more effectively but after a meal, particularly containing fat, then this ability can be significantly reduced.

Smell is the most highly developed of all the dog's senses. This is why an elderly dog which may be almost totally blind is nevertheless far less handicapped than a partially-sighted person.
© Contadini