Experts estimate that a single SAR dog can accomplish the work of 20 to 30 human searchers. It's not just about smell, either -- dogs' superior hearing and night vision also come into play. Time is always an issue in search and rescue. In an avalanche situation, for instance, approximately 90 percent of victims are alive 15 minutes after burial; 35 minutes after burial, only 30 percent of victims are alive. While most avalanche victims don't survive, their chances increase exponentially when dogs are in on the search. Even in cases where victims are presumed dead, dogs are invaluable assets -- they locate the bodies so family members can have closure and give their loved one a proper burial.
SAR dogs can do a lot of amazing things, including rappel down mountainsides with their handler, locate a human being within a 500-meter radius, find a dead body under water, climb ladders and walk across an unstable beam in a collapsed building, but it's all toward a single end: Finding human scent. This may be in the form of a living person, a dead body, a human tooth or an article of clothing. SAR dogs find missing persons, search disaster areas for survivors and bodies and locate evidence at crime scenes, all by focusing on the smell of a human being.
To people, this may seem like a difficult task. But to dogs, whose sense of smell is about 40 times stronger than a person's, it's a snap. To a dog, the scent of a human is as powerful and distinctive as the smell of a freshly baked apple pie is to a person. Human beings are smelly creatures -- they constantly shed dead skin cells called rafts, which contain bacteria and smell distinctly human. While it's impossible to know for sure, most experts believe that SAR dogs are smelling these rafts, which form a "scent cone" that the dog can easily pinpoint, when they're performing a search. Everyone's skin cells smell unique, which is how a dog can smell an item of clothing and search specifically for the last person who wore it.
While some dogs exhibit a stronger desire to scent than others, every canine out there has a powerful sense of smell. SAR dogs may be purebreds or mutts. Some handlers have a breed of choice, but any medium-to-large dog in good physical health, with decent intelligence, good listening skills, a non-aggressive personality and a strong play/prey drive (an intense, enduring desire to retrieve a toy) can potentially go into search and rescue. SAR dogs need to be big enough to successfully navigate treacherous terrain and push debris out of the way and yet small enough to transport easily. You actually don't find too many Saint Bernard search dogs these days, because they can be cumbersome. German shepherds are a popular SAR breed -- they're typically smart, obedient and agile, and their double-layered coat insulates against severe weather conditions. Hunting and herding dogs like Labrador and golden retrievers and border collies tend to be good at SAR work, too, because they have a very strong prey drive. Many people consider bloodhounds to be the best breed for tracking -- their giant ears and facial folds serve to collect and concentrate scent particles right at their nostrils, making their sense of smell extremely powerful and discerning. A bloodhound can pick up a trail weeks after other breeds can't find it.
This brings us to a distinction between types of SAR dogs: Some dogs track, while other dogs search.