A K-9’s nose is one of their greatest assets. Estimates vary but dogs have 200 – 300 million olfactory receptors compared to 5 to 6 million in humans. In addition, the part of the dog’s brain that is devoted to analyzing scents is proportionally 40 times greater than in humans. This means that a dog’s sense of smell is 10,000 to 100,000 times more acute than humans and the K-9 has the ability to identify each and every component of a scent individually.
K-9s are extremely useful when locating and identifying weapons, clothing, and other evidence that has been in contact with a particular suspect. Every time someone touches something, they transfer their scent to it. When a K-9 finds an item such as a gun or other evidence discarded by a suspect during a chase for example, the dog can actually identify the suspect’s unique scent on that particular item.
Dogs can be trained to identify a wide array of scents such as drugs. It is nearly impossible to hide the scent of drugs from a K-9. While a body search of a suspect may be illegal in many cases, a K-9 can sniff the air around a suspect and signal his handler if it detects the smell of drugs. If drugs are detected, the K-9 alerts his handler to the presence of drugs by sitting and placing his nose next to the source. This gives the officer probable cause to conduct a body search to recover the evidence.
Drugs are often transported in hidden places in cars, trucks or boats. Suspects go to great lengths to hide the drugs and their odor. They may multiple layers of plastic bags, even with soap or gasoline or other substances in between the bags to attempt to mask the odor. When a trained drug dog is employed such efforts are usually futile as the dog can detect even the faintest scent of most drugs.