Dogs aren't just man's best friend. They are able to do a lot more than chase a ball and bring it back. Dogs have been trained to find people buried under debris, lost in the mountains or otherwise missing. You can see them in airports, border crossings and used by police to sniff out contraband. They may even be able to smell cancer!

Search and Rescue Dogs

In the Netherlands, Search and Rescue dogs (called SAR dogs) learn how to sniff out people following their scent. A tracking or trailing dog follows the scent of particles that fall from victims, like dandruff or skin pieces. A dog searching for living people also tracks the scent of breath and sweat. SAR dogs looking for dead people only follow the scent that belongs to the victim such as human tissue.

Contraband Sniffers

You've seen these dogs at airports sniffing luggage for drugs and other contraband. Mike Ferdinand from Interquest Detection Canines says they generally use hunting breeds like Golden and Labrador Retrievers but not only for their sense of smell. "They have a good disposition, excellent working life and are great around kids." But how do they smell contraband? "The dogs are trained on a positive reward system. Every time they smell the scents they are trained on, they get to play with a toy," says Mike. When they do smell contraband, the dogs are trained to sit immediately. Mike calls this a passive alert dog. For retrievers, sitting is something they struggle with since they instinctively want to retrieve. Beagles are another commonly used dog for their tracking skills and sense of smell.

Cancers Catchers

One of the more recently discovered skills dogs have, is the possible ability to smell cancer. Take George for example - this Schnauzer learned to smell cancer by retrieving a tube that had a melanoma sample in it. When George found the tube he was given a treat. Eventually George was put before the real test - humans. When George came across the a patient with cancer he sat down and gently tapped them with his paw. Out of the seven test patients, George identified five with cancer.

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