Bloodhound

Bred originally to hunt deer and wild boar these dogs are used now to track human beings by their scent. Bloodhounds are known for their special ability to follow scents for hours, even a full week over great distances. Commonly used by police and law enforcement all over the world to track escaped prisoners, missing persons, and even missing animals. Other breeds of scent hounds are English Foxhound, American Foxhound, Coonhound, Swiss Jura Hound, Bavarian Mountain Hound and many others.

A common misconception is that bloodhounds run in packs tracking down the scent. Sometimes this may be the case in places like England but in North America bloodhounds are used as solitary trackers. When Bloodhounds are on a trail they usually are silent and do not bark or howl as other scenthounds. The original use of the bloodhound as a leash-hound is to find the scent but not disturb animals or let prisoners know that the Bloodhound is on their trail. This requires silent trailing.

The bloodhound can follow a scent left several days into the past. Under optimal conditions, a bloodhound can detect as few as one or two cells. The bloodhound's nasal chambers larger than those of most other breeds. The large, long pendent ears serve to prevent wind from scattering nearby skin cells while the dog's nose is on the ground; the folds of wrinkled flesh under the lips and neck are called the shawl and serve to catch stray scent particles in the air or on a nearby branch as the bloodhound is scenting, reinforcing the scent in the dog's memory and nose.
Bloodhounds can weigh anywhere from 33 to 50 kg (80 to 110 lb), although some individuals can weigh as much as 72 kg (160 lb). They stand 58 to 69 cm (23 to 32 inches) high at the withers.
I think owning a Bloodhound would be a good idea, it would be great to have a Bloodhound around in case a loved one turned out to be missing!