Why are dogs called ‘man’s best friend’?

Language has a beautiful way of enshrining history. You love your dog – we love them too and we haven’t even met them – but the phrase ‘man’s best friend’ tells you that it’s a love that goes way back, a beautiful bond between humans and canines. Where did this love come from? Why did the phrase originate?

The history behind the bond

Humans and dogs go a long way back. Most researchers estimate the bond goes back around 45,000 years ago, when humans just started to establish a pragmatic and distant relationship with wolves: we feed you and you protect us. It was a win-win situation for both sides. Dogs also played a role as hunters or scavengers alongside human tribes, although the exact nature of their roles is unknown.

But over the years, that bond deepened and so began the evolution of the domestic dog. Canine bone structures changed and dogs became less wolf and more like the animals we know today. (Dogs still share 99% of their DNAs with wolves.) Proof of that bond exists in a grave in Oberkassel, Bonn, in German. This grave is estimated to be 14,500 years old and has skeletons of two humans and what was originally considered a ‘wolf’. But the remains were re-examined in the late 1970s to reveal the first remains of a domesticated dog.

The psychology behind the bond

The human–canine bond is not an abstract concept; there is real psychology behind it. In the 20th century, Boris Levinson discovered that children responded better to his therapy sessions when he brought his dog, Jingles, to the sessions. And so began pet therapy. From then on, dogs have been used in a variety of activities designed to help humans. We have therapy dogs that stay in nursing homes to comfort those who are ill, emotion support dogs that offer companionship to those suffering from mental illness such as depression and anxiety, guide dogs, mobility dogs, medical alert dogs. Research shows that dogs are exceptional companions and are able to smell fear, anxiety and illness. They really are incredible animals.

But it’s not just dogs that are affected or changed by the human-canine bond. Research shows that petting a dog releases oxytocin in a human’s brain; this chemical is not only responsible for happiness, but also for bonding and affection. It also releases serotonin and dopamine, all great reward chemicals. And there’s more. Petting a dog or hugging a dog can help lower blood pressure and heart rate, as well as improve heart variability (which is the ability of your heart to respond to stress).

And it gets better. Research shows that staring into your dog’s eyes can increase oxytocin levels in your brain and in your dog’s brain. Basically, it’s a positive feedback loop. You stare into your dog’s eyes and your oxytocin levels go up. As your dog stares into your eyes, their oxytocin levels go up and so they keep staring. As they stare, your oxytocin levels keep rising and you keep staring as well. You see what we mean? It’s incredible. And you know where else this positive feedback loop is found? In human–infant bonding. When a mother stares into her infant’s eyes, both their oxytocin levels rise and they keep staring, cementing a bond.

(Don’t stare into a feral dog or wolf’s eyes though. Prolonged eye contact is considered aggression. This positive feedback loop only works with domesticated dogs and your beloved pet at home.)

The origin of the phrase

But back to our original question – where did the phrase ‘man’s best friend’ come from? Well… As with anything famous, there are disputed claims . Voltaire would probably like to staked a claim to it. In 1764, he wrote: “It seems that nature has given the dog to man for his defense and for his pleasure. Of all the animals, it is the most faithful; it is the best friend man can have.” But then there’s a poem in 1821, published in the New York Times , with the phrase:

“The faithful dog – why would I strive

To speak his merits, while they live

In every breast, and man's best friend

Does often at his heels attend.

Did that introduce the phrase into popular vocabulary? The town of Warrensburg, Missouri would disagree. According to them, it’s a court case in their town that made the phrase famous. In 1870, a farmer sued for damages when his dog was killed, and his lawyer’s closing speech mentioned: “The one absolutely unselfish friend that a man can have in this selfish world, the one that never deserts him and the one that never proves ungrateful or treacherous is his dog.” It doesn’t quite have ‘man’s best friend’ in it, but we can give them poetic license.

So there you have it. There’s no real origin of the phrase ‘man’s best friend’ or at least not one we can agree on. Still others claim the phrase began with Fredrick the Great, King of Prussia (1740–1786), who used to call his beloved Greyhounds his best friends. He is buried with them. And we’re sure that someone, somewhere used the phrase much before any of this and history has now forgotten.

So don’t think too much about where it came from – pick a favourite origin story and go with it (ours is Voltaire). Instead, step out and play with your beloved dog. It’s scientifically proven that it’s good for the both of you.