How do Search and Rescue Dogs Work?

Ever wondered why dogs are the animals used for search and rescue operations? What is it about their noses that makes them unique? Just what situations do they work in, exactly? Read on to learn the answers to these questions (and a fair bit more)!

Photo credit: Peter Hershey (Stocksnap)

Search and Rescue Dogs (SAR dogs) are employed by humans for a wide variety of tasks: they can help find people who are lost in the wilderness, patients who have wandered away from a care facility, or humans stuck in debris after a natural disaster like an earthquake, or snow after an avalanche. These trained dogs work well under pressure and have saved countless lives, well-earning the title of "heroes". Some suggest that a single SAR dog can do the work of 20-30 human searchers.

You've probably heard that dogs have an amazing sense of smell, but do you know why? Dogs have over 100 million (some studies suggest between 125-300 million) sensory receptor sites in their nasal cavities (which is how they detect scents) while humans have 6 million. Plus, the part of the brain that analyzes scents is 40 times bigger in dogs than in humans! Dogs can likely smell anywhere between 1,000 and 10,000 times better than humans, so it's no wonder that they're chosen for rescue work!

Canines also seem to smell "in stereo", meaning that their nostrils are pulling in air from different directions and at different rates, thus providing them with a better clue about where a particular scent is originating from. There are folded passages inside a dog's nose called turbinates (they have a lot more than us humans) that filter smells to different parts of a dog's nose. There are also turbinates that warm the air a dog inhales before it gets to the dog's lungs (grey wolves have to breathe in lots of cold air in the winter, so that is evolutionarily likely where this came from).

Photo credit: Rishi (Pexels)

It's also worth noting that dogs are one of the species of animals that has a Jacobsen's organ, which, when present in canines, functions as an additional olfactory organ. This organ is found in the nasal cavity and has nerves that lead right to the brain. In dogs, these special nerves have cells that respond to substances that don't normally have an odor at all! This organ is quite controversial in humans, as its presence has been documented in many humans, but not all, and its purpose in humans is widely debated.

SAR dogs are trained to smell the dead skin cells of humans, called rafts. Humans shed these all the time, and they are distinctly human-smelling because of the bacteria on them. Plus, everybody smells different enough for canines to distinguish between one person and another quite easily, so a SAR dog can latch onto a unique scent and track it. Oftentimes, SAR dogs use scent cones to find the origin of the scent.

When you see a SAR dog circling while they're on the trail, they're circling because the scent likely got broken up and they're trying to pick it up again to find where it's strongest. Odor isn't a uniform shape, it spreads and gets stretched and pulled by air, so sometimes trackers need to circle a little bit to pick back up where they left off. Sometimes travelling along the edge of an odor plume is best because it provides context for where the smell is, where it isn't, and where it's originating from. If you're in the middle of the scent cone/odor plume, you're surrounded by the smell and might have a harder time telling where it's coming from.

Photo credit: International Fund for Animal Welfare (Pexels)

Not all SAR dogs are the same! There are actually two main types of SAR dogs: air-scenting and trailing.

Air-scenting SAR dogs typically focus on detecting airborne human scent in general rather than a specific person's scent, frequently working off-lead to cover large areas. These dogs are extremely helpful in natural disasters (not just limited to that of course), as there isn't a specific person they are looking for, but rather any human in distress. They track the smell until they find where it originates from, and they alert their handlers by barking or by going to retrieve them and guiding them to the lost person.

Weather is actually an important consideration when evaluating the SAR dogs' ability to work. Everything from wind speed and direction to temperature and humidity can affect SAR dogs' jobs, as they track scents based on air-borne particles. Even in less-than-ideal conditions, however, SAR dogs can cover a search area of up to 150 acres! They can detect scent sources from as far as 1/4 of a mile away.

Canines generally have an amazing sense of smell, but some breeds work most efficiently as air-scenting SAR dogs. One can frequently find Labrador Retrievers, Golden Retrievers, Springer Spaniels, German Shepherds, Border Collies, and other herding or sporting breeds on an air-scenting SAR dog team.

Photo credit: Amal Santhosh (Pexels)

Trailing SAR dogs discriminate the scent of a specific person after being given something like clothing from the missing person that has their scent on it. These are the sorts of dogs that are often portrayed in movies, the ones that keep their noses to the ground for the most part (sometimes raising their heads to detect airborne particles). They work both on- and off-lead and are able to detect the actual path that the missing person took, including turns or double-backs the lost person took. They detect the scent on the ground and vegetation, ignoring other human scents and animal scents and honing in on the scent of the lost person, sometimes referred to as the "scent of the day". They often work on-lead and move slower than air-scenting SAR dogs.

Many people associate this type of tracking with Bloodhounds, and for good reason! Bloodhounds are adept at tracking, as their giant ears and facial folds are especially good at collecting and concentrating scent particles directly at their noses. Hounds also often have a strong tracking drive, as they were bred for that trait in particular, but that doesn't mean other dogs can't be astounding trackers.

As in air-scenting SAR dog teams, herding and sporting breeds can often be found in this position, as well as working breeds. Oftentimes, larger, more athletic breeds are used because they can work well on rough terrain and in difficult conditions, which they sometimes have to face on the job. Of course, their handlers have to be able to handle these conditions too. Search and rescue missions are no walk in the park (though SAR dogs love those too).

Photo credit: Matt Bango (Stocksnap)

A dog who's a good fit for search and rescue work usually has the following traits:

• Medium-to-large size (big enough to navigate terrain and push objects out of the way, small enough to transport to site easily)
• Good physical health (hearing, sight, strength)
• Intelligent
• Good listening skills
• Non-aggressive personality
• Strong play/prey drive (intense, enduring desire to retrieve a toy)

Sometimes both types of SAR dog might be employed together: the air-scenting dogs would be released in the most likely places for a person to be and search a broad area. The tracking dogs would be taken to the missing person's last known location or the site of a piece of evidence and go from there. The dogs in both parties must be able to work 4-8 hours without break or distractions. Their handlers must understand and be able to apply survival techniques and be able to withstand the same conditions.

Photo credit: Humphrey (Stocksnap)

There are a few types of specialization that SAR dogs can be trained in:

• Human Remains Detection (HRD) or Cadaver
• These dogs are trained to find the remains of deceased persons through the detection of human decompositions gasses in addition to the skin rafts they normally know how to scent. They can scent something as small as one drop of blood. Air-scenting and trailing dogs can both be trained in this way, and they can work in larger natural disasters or on localized, specific crimes.
• Water
• Dogs are taken out on boats to search for drowning victims. Even if the body is far, far underwater, the skin particles and decomposition gasses will still rise to the surface. Water currents make exact location difficult to determine, so usually there are multiple SAR teams searching the area to triangulate where the body/ies might most likely be.
• Avalanche
• Avalanche-trained SAR dogs can detect the scent of humans buried under snow. These dogs also have to be able to efficiently navigate in a dangerous area like a mountain post-avalanche, and they can detect the scent of humans from up to 15 feet down. These aren't the only dogs who need to be able to rappel down mountains with their handlers, but it's especially a necessary skill for those trained in the avalanche specialization.
• Urban Disaster
• The danger of collapsed buildings after an urban disaster makes this the trickiest SAR specialty, as these dogs have to consistently navigate a treacherous environment for long stretches of time. The narrow, unstable beams of a caved-in building are hard to maneuver, but these dogs must be able to do it. Some SAR dogs must also be trained to climb ladders.
• Wilderness
• Wilderness settings can also be a specialty, where there might be many other natural prey scents for a dog to get distracted by  but not a well-trained SAR dog.
• Evidence/article
• This branch of training focuses on the SAR dogs searching for items that have human scent on them. The goal of SAR dogs is to find human scent and follow it: dead, alive, a body part, even a scrap of clothing.

Photo credit: Pixabay (Pexels)

Even if a SAR dog hasn't been specifically trained to detect human remains, they will alert their handlers if they find them. However, those who are trained to find living people get discouraged when they only find dead bodies, as their training and their handlers' reactions when they find live people have conditioned them to understand that live humans are preferable finds. Sometimes, during a major urban disaster, handlers and firefighters have hidden in the rubble to give the dogs a living person to find to keep their spirits up. The dogs need to be confident in their abilities to complete the task, because uncertainty can lead to hesitation when there is no time to spare. Time is an incredibly important aspect of SAR work. Strength, agility, and obedience are three other key factors that SAR dogs typically need to be successful.

That's why there are firm SAR standards. Both types of SAR dog need special SAR training, and a lot of it. Puppies are trained from 8-10 weeks old and are usually working by 1-1.5 years of age. They start with basic obedience and then move on to tracking, handler signaling, and appropriate behavior in stressful situations. They get to retire when they're between 5-10 years old, having more than earned the right to go home (often) with their handlers, where they're often already an important part of the family. SAR dogs have a difficult and physically demanding occupation, and they are rightfully considered heroes by many. If you'd like to read about more hardworking canines, we have an article about that here.

Photo credit: Tobias Aepelli (Pexels)

Sources:

Akpan, Nsikan, and Matt Ehrichs. “Inside the Extraordinary Nose of a Search-and-Rescue Dog.” PBS, Public Broadcasting Service, 12 Aug. 2016, www.pbs.org/newshour/science/inside-nose-rescue-dog.

Buzhardt, Lynn. “Search and Rescue Dogs.” VCA Hospitals, vcahospitals.com/know-your-pet/search-and-rescue-dogs.

“Canine Teams.” Colorado Forensic Canines, Colorado Forensic Canines, 2014, www.findthelost.org/teams.

Layton, Julia. “How Search-and-Rescue Dogs Work.” HowStuffWorks, HowStuffWorks, 16 Dec. 2005, animals.howstuffworks.com/animal-facts/sar-dog1.htm.

Pessah, Steve. “Search and Rescue.” American Kennel Club, 28 Nov. 2017, www.akc.org/sports/title-recognition-program/search-and-rescue/.

Rascoe, Kelli. “Search and Rescue Dogs: How to Get Involved.” The Trupanion Blog, 18 Mar. 2019, trupanion.com/blog/2019/03/search-and-rescue-dogs/.

Search and Rescue Dogs of Pennsylvania, Search and Rescue Dogs of Pennsylvania, www.sardogs.org/.

Search and Rescue Dogs of the United States, sardogsus.org/.

Written by Skye Isabella Rose Iwanski