Dogs & us - The secrets of an unbreakable friendship | DW Documentary

They're playful, headstrong, fun-loving, and above all loyal. Our emotional connection with them, stemming back thousands of years, remains unbroken to this day. Their evolution, millennia in the making, has made them perfectly suited to us.

"I'm working with somebody who's really much, much cleverer than me. Their phenomenal senses make them an indispensable member of any team, and their great sense of smell means they can detect diseases even in their earliest stages. They saved my life."

For some, a dog offers a last glimmer of hope. "It's really like having my best friend in the world right here in the cell with me. You know what I mean? Like sometimes I don't want to talk to anybody else, but I always want to hang out with my dog."

What makes them so unique in the animal world is their ability to communicate and understand us. Your dog is smarter than you think. But why did dogs become our ideal companion and co-worker? Why are dogs so loyal that they would follow us to the ends of the earth? What exactly is the secret behind this unique friendship?

Inset: a small town in northern Norway, kilometers north of the Arctic Circle.

The Greenland dogs here are the living inheritors of the ancient wolf's genome. They belong to one of the oldest dog breeds in the world. Here, humans and dogs still lead a life left untouched by modernity.

"I emigrated from Hamburg 30 years ago and set up a husky farm here. When I first started offering guided tours, my main goal was just being outside. I wanted to be out in nature with the dogs. It's kind of like living the life of a farmer who keeps to himself and doesn't get around too much. And even though I haven't seen very much of the world, somehow I can really say that I have found one of the most beautiful spots on earth."

It all started when Bjorn Klower was on a hiking tour across Norway. He longed for a solitary life away from society. A Greenland dog joined him on this journey, not only pulling his bags but also keeping him company. Without the dog, Bjorn would have grown very lonely.

Greenland dogs are just perfect for these extreme expeditions in the far north. Their thick fur protects them from temperatures as low as -40 degrees Celsius. They are sled dogs through and through.

Bjorn's routine with the dogs is dictated by the weather. In winter, he spends more than 100 days in the great outdoors. Each day, these bundles of energy run up to 60 kilometers. It is on these trips that Bjorn and the dogs have forged their special bond.

"The lead dog runs out in front of the team. He is the one that I communicate with, who I have direct contact with. He always wants to do everything just right, just like all dogs. He wants to do everything right for his owner. But you have to build trust with the lead. That means the dog must first know that my commands are actually always good. I won't ever put them in danger. On the other hand, if the dog backs away from something, I must also know, 'Okay, there's got to be something in the way.' Your dog is basically your life insurance policy out here. And it trusts you no matter what."

The highlands of northern Norway: seemingly endless, lonely tundra covered in dense snow for more than half a year. What has now become a passion for Bjorn was once essential to the survival of our Nordic ancestors.

Sled dogs and humans have shared a close relationship for more than 2,000 years: with nomads in Siberia, with Inuits, the natives of North America, and with the inhabitants of Greenland, the home of Bjorn's Greenland dogs.

In a landscape dominated by ice and snow, our ancestors were dependent on their dogs. And not only for hunting. With their sleds, they were able to reach other settlements to buy and sell goods. The dogs played a key role in expanding trade routes.

Even at this point in time, dogs proved themselves to be highly sociable animals. These endearing traits have endured until today. Dogs are the only working animals in the world that you cannot pressure to do what you want them to. They just have their own motivation.

And if the snow is really deep, I may have to go grab my snowshoes. And it is this collaboration, in my opinion, which is the greatest experience. This really deepens our connection with nature even more.

For thousands of years, sled dogs have been at our side, ready to help. And in the process, they've learned to understand us.

When I'm there, standing on the sled and watching the dogs having fun, just running, and when I take in the mountains and enjoy the scenery, that's an unbelievable sense of freedom.

Our relationship with dogs is really quite remarkable. Dogs are among the few animals that can respond to where we look, where we point, and how we speak. According to recent studies, dogs are not only able to interpret our tone of voice but actually understand exactly what we are saying to them. Researchers have found that dogs only feel appreciated when both our words and tone express praise. Also, how a dog tilts its head gives us another clue about how they understand the language. It suggests that dogs process speech in much the same way as we humans do. Meaningful words are processed in the left half of the brain, and the tone of voice in the right.

The unique, sophisticated ways in which we are able to communicate with dogs have changed lives.

Dogs have taken on tasks that humans otherwise could not do on their own. These sheepdogs are very compulsive in their nature; working sheep is almost like a drug to them. They love that drug, so they'll do anything to have the pleasure of hunting and working sheep.

Here on the English-Scottish border is the home of the world's most famous herding dog, the Border Collie. Derek Scrimgore has lived in the mountains of Cumbria for the last 50 years. Besides running a sheep farm, he specializes in breeding Border Collies.

"The minute I started to work with a Border Collie, I realized this completely different type of dog," he says. "It was clever and it wanted to please me. And the whole concept of the dog working sheep, it's like magic. It felt like magic, and it was just so intriguing."

Compared to humans, dogs have a much more extensive field of vision. This is what makes them true masters of herding. While we perceive our environment like this, dogs see the world pretty much like this, with a field of vision of about 250 degrees. This means they are very sensitive to the movements all around them. This heightened awareness helps them watch over the sheep at all times and to instantly recognize dangers.

But what is most important is communication. Lynn listens carefully to Derek's commands. These brief commands are enough to let Lynn know which sheep she needs to take and where. Her work is a balancing act between obedience and acting on her initiative.

"These dogs will run out so half a mile easily and take directions left and right to fetch sheep to where we want them," Derek explains. "I don't know anybody who can take direction like a dog. If anybody sort of gave me as many directions as I give my dog, I think I could stand it for about maybe 20 minutes before I left, where these dogs will work all day and take advice and try to be helpful and keep an open mind which is so they're very useful."

The ancestors of the Border Collies lived in England and Scotland in the 16th century. Here, shepherds discovered their skills and developed them even further, especially on large barren pastures. These dogs became indispensable. Only with their help could shepherds lead their sheep to fresh pastures and water.

Even today, working in this vast landscape would be impossible without the dogs. The sheep are more than 800 meters away, but the shepherds can communicate with their dogs across this distance. Derek fully trusts his dogs, and they, in turn, trust him.

There, now, come by, lay down there, Derek instructs. He teaches his dogs to channel their natural hunting behavior into their herding. To do this, the dogs use their special skills derived from hunting: targeting prey, stalking it, and circling and getting their prey right where they want it.

For shepherds like Derek, the Border Collies are just as valuable as they were centuries ago. Every day, every minute of every day, he just enjoys working with the dogs. And especially when he gets one that's a little bit better, something that's a little bit special.

"Sometimes you get a dog, it's just a little bit of a genius in dog terms," he says. "He's much more of a genius than I could ever be. And I'm working with somebody who's really much, much cleverer than me. So this dog I've got just now, Lynn, she's an example of that. She was born to work. The minute she started working, it was almost as if she'd been here before."

Even to this day, many shepherds and herders around the world are only able to overcome their challenges with the help of these trusty dogs.

Dogs, with their desire to work and live with humans, are quite unique in the animal world. Researchers even hypothesize that dogs have played an important role in our own development. Without our close relationship with dogs, humans would probably not be where they are today.

One ability that has made dogs particularly important to us is their keen sense of smell. Unlike humans, dogs spend their lives immersed in a world of sense.

In Gratvine, Styria, Austria, here we meet some dogs that science is only now starting to catch up with. Today, Franz Huggle is visiting Wolfgang and his dogs Rocky and Lucy. Although he was having regular checkups by his urologists, it was the dogs that were able to detect his prostate cancer in its initial stages. Could these dogs really have done that? It's revival. So why shouldn't they find cancer in the end? Those dogs saved my life.

Wolfgang trains these cancer detection dogs at this farmhouse. Just over 10 years ago, this former police dog handler founded the world's first cancer detection canine team. It is all run entirely on donations. Despite widespread skepticism, those who believe in these dogs' unique talents are regularly sending out tubes filled with breath, urine, and saliva.

The new samples are placed in a beam to make sure that the dogs' nose is working properly. They include negative and positive control samples in the setup. But what exactly can these dogs smell?

Cancer detection dogs are trained to detect odors released by certain tumor cells. Cancer cells are known to release alkaline odors. These scent molecules have been detected in breath samples from lung cancer patients and in the urine of prostate cancer patients. And it is exactly this odor that the dogs should be able to recognize.

Wolfgang needs to make sure that Rocky sniffs each sample thoroughly so that no odor escapes his nose. Each cancer detection dog has developed their own individual signal when they find something.

"I will statements get to my mention. You always have to keep in mind that a human life is at stake. I feel like you cannot take this work lightly. You have to be careful to keep the error rates as low as possible."

After each round, the beam is disinfected to get rid of odors left by the other dogs. Then the setup is repeated, placing the probes at different positions. This is repeated five times with five different dogs to do a thorough cross-check.

"We test and evaluate samples at least 15 times before we consider it's positive or negative."

Working under the close supervision of pulmonologists, Wolfgang conducted tests confirming the overwhelming accuracy of his trained sniffer dogs. From over 2,200 documented cancer cases, 93% of their results have turned out to be correct