How Humans and Dogs Evolved Together

July 12, 2025

The Evolution and Domestication of Dogs

By at least 14,000 years ago, dogs had fully entered into a relationship with humans and earned their place by the campfires of the many hunter-gatherer societies that existed at that time.

They were already distinct from gray wolves in appearance—and most likely in temperament as well. Most of the changes these Paleolithic dogs had undergone were for the benefit of humans. But in the story of domestication, we often take too much credit, as dogs have shaped us in many ways, just as we have shaped them.

Origin of Dogs

It is widely accepted that dogs descended from gray wolves. There is no evidence of any other canines being involved. However, the gray wolves alive today are not the direct ancestors of dogs—they actually descended from a population that is thought to have gone extinct toward the end of the Ice Age.

Genetic studies show this divergence took place around 40,000 years ago, which sets the highest boundary for when dogs could have been domesticated. However, the first true dogs probably appeared much later, as actual dog remains found in human settlements tend to be dated after this period.

There are several canine remains from around Europe and Western Asia proposed to be domesticated dogs, one of the oldest being found in a cave in Belgium, dated to 36,000 years ago. However, its classification as a truly domesticated dog is controversial.

The Challenge of Defining Domestication

It's difficult to pinpoint exactly when dogs were domesticated because populations of animals can evolve tiny differences quickly—just enough to adapt to slightly different environments. This makes it hard to tell whether a specimen is a domesticated dog or just an extinct population of gray wolf with subtle differences.

Adding to the difficulty is the fact that 10,000 to 60,000 years ago, wolf populations were more diverse than today. For instance, Ice Age wolves like the Beringian wolf and megafaunal wolves in Europe had broader skulls and shorter snouts—adaptations for hunting larger prey such as horses, bison, elk, and possibly the giant deer (Megaloceros).

From about 15,000 to 13,000 years ago, we find specimens throughout Western Europe that scientists confidently identify as domesticated dogs. One famous example is the Oberkassel dog found in Germany. After this point, dogs spread throughout Eurasia.

Two Domestication Events

It is highly likely that all modern dog breeds descend from two major domestication events. The second event occurred in Asia about 12,000 years ago and is considered the origin of many Asian dog breeds today.

Why Were Dogs Domesticated?

The exact reasons why or how dogs were first domesticated remain uncertain—and likely always will. It's a process that’s difficult to find direct evidence for, and the discussion rarely goes beyond educated speculation.

Dog domestication was likely not a conscious effort by humans—at least in the beginning. This is in contrast to livestock animals, which were most likely captured and purposefully bred for food.

Wolves are the only large carnivore humans have ever domesticated. Pre-domestication interactions were probably hostile, and it’s unlikely early humans could predict how useful dogs would become.

The Early Human–Dog Relationship

Dogs likely began their relationship with humans by scavenging near human camps. The smell of food or discarded scraps may have attracted them, and humans may have tolerated the less aggressive wolves, as they could help alert to danger or intruders.

Over time, these early interactions may have led to unintentional domestication. In fact, it might be no accident that the first domesticated animals were carnivores, since carnivores are less timid and more likely to approach other species.

It’s even possible that dogs inspired the domestication of other animals.

Co-Evolution of Dogs and Humans

As dogs began to live alongside humans, they were thrust into a co-evolutionary journey.

Dogs became more socially attuned to humans, even more so than our closest relatives like chimpanzees. For example, dogs can reliably respond to pointing gestures, whereas chimpanzees struggle with this without training.

But this wasn’t a one-sided development—humans changed too. Interactions with dogs led to an increase in oxytocin, the “bonding” hormone, in both dogs and humans. Interestingly, when the same test was conducted with hand-raised wolves, the same chemical response didn’t occur in humans. This suggests that humans evolved alongside dogs in this relationship.

From Carnivores to Omnivores

When humans transitioned from hunter-gatherer lifestyles to agriculture, they evolved to better digest starchy foods like wheat and rice. This included duplications of the amylase gene—an enzyme that begins starch digestion in the mouth.

Dogs evolved similarly.

Whereas gray wolves and dingoes have 2 copies of the amylase gene, dogs from agricultural regions developed many more, allowing them to thrive on human leftovers and starchy diets. For instance:

Huskies, bred by the Chukchi people of East Russia, have only 3 copies, since their diet was mainly meat.
Salukis, bred in the Middle East where agriculture began early, have up to 29 copies of the gene.

Dogs in Diverse Climates

Dogs didn’t just follow humans to different latitudes—but also to different altitudes.

Take the Tibetan Mastiff, bred in the Himalayas, often living above 4,000 meters. These dogs were able to survive due to gene flow from local Tibetan wolves—a type of natural genetic adaptation that allowed them to resist hypoxia (low oxygen).

Surprisingly, this mirrors the way Tibetan humans adapted: by inheriting a gene from Denisovans (an archaic human species) that helped them regulate blood oxygen levels at high altitudes.