How do search and rescue dogs train to find missing people?

Today, there are about 350 civilian search and rescue dogs in Norway that have been approved and certified by Norwegian Search and Rescue Dogs, a volunteer organization.

“The nearest crews are often called by the police or the main search and rescue centre when they have been notified that there’s a missing person in the area,” says Bjørn Tore Olsrud, a member of the Norwegian Search and rescue Dogs' technical committee.

The technical committee is responsible for training new search and rescue dogs. Both the dog owner and the dog must pass courses to be approved as search and rescue crew.

Most dog breeds can be used

Most dog breeds can be trained to be search and rescue dogs, including shepherds, retrievers and giant schnauzers. Mixed breed dogs can also be trained. Many of these dogs have an innate instinct to herd animals or retrieve game, such as shepherds or bird dogs.

“It’s definitely an advantage if they are neither very small nor very large,” says Ulsrud.

But instinct is not enough. These dogs need lots of training. The dogs have to be at least two years old to be certified, and training can well start before that. Dog handlers must be at least 18 years old.

Search and rescue dogs in 400-500 searches per year

Search and rescue dogs can look for missing people on the ground and who have been buried in avalanches.

“We are called out on about 400 to 500 search operations a year,” Olsrud says.

The crews must have completed courses and passed tests in the various relevant subjects.

The dogs find missing people in about 10 per cent of the cases, according to Olsrud.

“We find more people who are living rather than dead,” he says.

Dogs love to work

Kristin Paaske Anfinsen, who works as an associate professor at the Norwegian University of Life Sciences, NMBU, has participated in search and rescue activities.

“We train with a team and there’s a lot of interaction between the dog and owner,” she said.

The dog has an inner motivation, which is directed towards searching and finding, and is rewarded for its discoveries, either in the form of treats or toys.

Her dog, Nemo, gets to play with a squeaky ball as a reward.

“This gives the dog positive reinforcement, and my dog thinks this kind of ‘play’ is the greatest thing in the world,” she says.

For personal reasons, Anfinsen has not renewed her certification, but will do so as soon as she has the opportunity.

“My experience really made me want to be involved in more search and rescue efforts,” she said.

Their sense of smell is unbelievable

It is said that if a dog’s sense of smell extended the area of a football field, the equivalent in humans would be one postage stamp. Lars Moe, a professor at the Veterinary College at NMBU, says that’s probably about right.

“This may well be true. A dog’s ability to smell is extremely good, a few molecules are enough,” says Moe to sciencenorway.no.

“Dogs can even be trained to smell people who have been infected by COVID-19, even before they have clinical symptoms,” he said.

Moe is a veterinarian and professor at the Department of Companion Animal Clinical Sciences at NMBU.

Part of the sense of smell is innate ability. Bird dogs are good at finding birds by catching a scent in the air from grouse lying on the ground. Hunting dogs can look for other prey by following tracks on the ground.

In addition, people have further developed their ability to find things by training them to search for specific odours and to signal that they have detected them, he said.

Rewards are key

But how is a dog taught these skills? What does it take for dogs to understand what to find?

“The training begins with markers in the form of people lying down or hiding in the landscape. The dog is encouraged to find the person. It gets a reward in the form of a treat or a favourite toy when they find the person,” Olsrud from Norwegian Search and Rescue Dogs explains.

Gradually, the dogs are given more difficult tasks. The coaches build on the training, step by step.

“They get to train in more difficult environments, where the markers are more well hidden,” Olsrud says.

The dogs are also trained to signal when they find clothes, backpacks and other things that people have worn.

They signal either by standing on the spot and barking, or return to the owner with a leash that it bites.

When they make discoveries, they are always rewarded.

“We are looking for dogs that like to work for hours, so rewarding them is important,” Olsrud said.

Dementia or suicide candidates

The vast majority of searches are for people with dementia who have died, or psychiatric patients.

“These are depressed people who may be considering taking their own lives,” Olsrud said.

But a few searches are for ordinary hikers who have gone missing.

Search and rescue dogs can also be used in disaster areas such as collapsed buildings or landslides, if the crew has been approved for that specific type of search.

Extremely good sense of smell

Search and rescue dogs on land can get additional training, such as for avalanche searches and rescue and disaster training. These require separate courses that the dogs and their handlers must pass. During the tests, people are buried in large cavities, large enough so they have space to breathe.

A dog’s sense of smell is so good that they can find people buried deep in the snow.

“Even in snow, there will be air pockets that allow dogs on the surface to smell people who are several metres under the snow. The human body is warm, and the smell rises,” Olsrud said.

Searching in landslides is far more difficult.

“In the case of landslides, the area of the slide is almost like a vacuum, and it can take a long time for the dog to identify odours,” he said.

Not happy when they find victims

Does a search and rescue dog know that it might find the living and the dead?

“Dogs don’t inherently think that something smells bad. But we see that when dogs signal that they have found a victim, they’re nowhere near as happy as when they find a living person,” Olsrud said.

They don’t wag their tails, but are more subdued.

“It may be that they understand that the person is dead,” he said.

Working with forensic medicine

To teach the dogs what dead people smell like, Norwegian Search and Rescue Dogs previously had an agreement with the Department of Forensic Medicine at the Norwegian Institute of Public Health (NIPH), which has now been moved to Oslo University Hospital.

“We were able to borrow clothes from people who had died while wearing them, so the dogs could train with that smell,” he said.

A few years ago, this agreement ended. Olsrud doesn’t know why.

“But there are a lot of ethical issues involved in this issue,” he said.

Using statistics to refine searches

Olsrud says that they keep their own statistics on successful searches that have led to discoveries. Based on what is known about the missing person, the search team decides on the size of the area they should search.

“Based on how far missing people from different groups tend to go, we prepare a plan for the most relevant exploration area,” he explains.

For example, they typically use one radius if they are looking for depressed or suicidal individuals.

People with dementia, however, often get stuck in one area of the terrain. They typically walk in a shorter distance from the place they were last seen, says Olsrud.

Search teams have maps of the area, where they put a pin in the last place the person was seen, and draw a circle around that area with a specific radius.

Norwegian search and rescue dogs work closely with volunteer search crews in other countries, such as Iceland, England, Malta, Italy and Germany.

“In Norway, Norwegian search and rescue dogs are used to a much greater extent by the police when people are missing, than for example in Denmark, where they carry out far fewer searches,” Olsrud says.

Smelled drugs that had been removed

Professor Lars Moe at the Veterinary College at NMBU has worked with training utility dogs, such as guide dogs, drug sniffing dogs, demining dogs for Norwegian People's Aid and visiting dogs for hospitals and nursing homes.

Moe talks about experiments with drug sniffing dogs he performed with the police a few years ago.

“We put out drugs, anesthetized the dogs and woke them up again, to see if they got back all their brain function, including the sense of smell after the anaesthesia. And they did,” Moe said.

The experiment was done every few weeks, and the dogs signalled that they detected the drugs even after the drugs had been removed.

“One of the dogs even signalled on a box in a shelf, where there had been drugs several weeks earlier, but that we had removed in the meantime,” he said.

Could smell COVID-19

Moe believes that working dogs are underused in Norway.

“Dogs can be trained to find fungi, including edible fungi and house mould. They can also be trained to smell cancer,” he said.

The latest is that dogs are being trained to smell COVID-19 even before humans develop clinical symptoms. This is being worked on in Germany and Finland, Moe says.

Moe thinks it was appropriate to stop the Gjerdrum landslide search for the last missing people for a brief period during the most intense part of the search, after which rested dog teams were brought in a few hours later.

“In these kinds of searches, it’s important not to contaminate the odours. Search areas are prone to being contaminated by too many people, or stray dogs, so that the dogs are unable to distinguish the smells,” he said.

“Consequently, the search area has to be cleared and ‘rested’ so as not to distract the dogs if the search takes a long time,” Moe said.

Translated by: Nancy Bazilchuk

Read the Norwegian version of this article on forskning.no.