Why Are Bloodhounds So Good At Tracking?

Whenever there's a chain gang jailbreak in a movie, you can always bet that a booming bellow of bloodhounds will soon follow. Where there's a fox on the run, there's a hound hot on its tail. When a little girl goes missing, best break out the padfooted blood bothers. Yeah, you get the picture. Bloodhounds, per their reputation, are perhaps nature's most supreme tracking devices on four legs. For as long as they've existed, these dogs have been used for search and rescue, hunting, stalking criminals on the run, and drug busts. It's almost as if they were... "scent" from another dimension. 

The rumors about bloodhounds being able to smell better than any other dog are true. In fact, their noses are so reliable, their findings in cases of legal investigation actually hold up in a court of law (via Sit Means Sit). But what are the biological mechanics that make those sniffly snouts so sensational?

So what makes their sense of smell so superior to other breeds? Well, there's a few things. Olfactory receptors – sometimes called "scent cells" – are cells congregated in the noses of different species. Their function is to detect odor molecules. Human beings on average have about 5 million olfactory receptors in their nasal passages, while dogs like German Shepherds have a concentration of around 225 million of them. Bloodhounds, in addition to foxhounds, beagles, and catahoulas, take things a step further and up those figures to a whopping 300 million olfactory receptors in their noses (per Mental Floss). 

Some other factors play into the phenomenon as well. Their droopy features and heavy stature aren't just for aesthetic purposes. The wrinkles and thickness in the folds of their skin collect odor molecules and push them in the direction of their noses, sharpening their already acute sense of smell. Bloodhounds also have muscular necks and shoulders that do two things: 1. weight their noses down and keep them close to the ground, and 2. help them to maintain the strength necessary to track for long periods of time without getting winded (via Mental Floss). In addition to being great dogs overall, bloodhounds have the whiff to go along with the woof.