Dogs, humanity’s oldest domesticated companions, may be entering a new phase of evolution as a result of thousands of years of living closely with humans. While the earliest domestication of dogs dates back at least 15,000 years, scientists now believe that domestication is not a static process.
Instead, it continues to shape dogs’ biology, behavior, and even genetics in real time. The ongoing relationship between humans and dogs is causing evolutionary changes that may lead to new traits and capabilities, marking what could be considered a new evolutionary phase.
It Began with Wolves
The initial domestication of dogs likely began when wolves started scavenging near human settlements. Over generations, the wolves that were less fearful and more social benefited from the proximity to humans and gradually evolved into the first domesticated dogs.
This marked the first major evolutionary shift, as dogs began to diverge from their wild ancestors both physically and behaviorally. Traits such as reduced aggression, smaller body size, droopy ears, and changes in coat color appeared during this early domestication phase.
Evolving in Their Own Ways
Now, with dogs fully integrated into human society, they are continuing to evolve, but in new ways. Unlike wild animals, whose evolution is largely shaped by natural selection, domestic dogs are subject to both natural and artificial selection.
Humans directly influence their breeding, behavior, and environment. As a result, dogs are adapting to human-centric lifestyles in ways that are reshaping their cognitive and physical traits.
One major area of change is in dogs’ social intelligence. Studies show that dogs have developed an exceptional ability to read human social cues. They can follow human pointing gestures, understand tone of voice, and even interpret facial expressions. These are skills that are quite rare in other animals.
Obviously, this is adorable but this also suggests that dogs are evolving to become better communicators with humans. A trait that offers clear survival and social advantages in human environments.
Dogs Are Changing—Genetically
Another indicator of evolutionary change lies in genetics. Recent studies have identified specific genes in dogs associated with behavior, stress response, and learning.
For example, research comparing ancient and modern dog genomes shows that dogs have developed more copies of the AMY2B gene, which is linked to the ability to digest starch.
This change reflects dogs’ adaptation to a diet shaped by human agriculture. This gene variation is not seen in wolves, highlighting how domestication has led to functional evolutionary differences in dogs.
Urbanization and modern lifestyles are also putting new pressures on dogs, potentially triggering further changes. In cities, dogs face noise pollution, artificial lighting, crowded spaces, and constant human interaction.
These conditions could favor traits like calmness, adaptability, and reduced fear response. Dogs that are better suited to urban environments may be more likely to reproduce or be chosen for breeding, accelerating genetic shifts.
Emotionally Linked: You and Your Dog
In 2017, researchers at Linköping University in Sweden conducted a groundbreaking study revealing that dogs' long-term stress levels synchronize with those of their owners. This study, published in Hormones and Behavoir Journal, provides compelling evidence that dogs may mirror their owners' stress, highlighting the deep emotional bond between humans and their canine companions
The research involved 58 dogs—25 Border Collies and 33 Shetland Sheepdogs—all owned by women. To assess long-term stress levels, the team measured cortisol concentrations in hair samples from both the dogs and their owners.
Cortisol, a hormone released in response to stress, integrates into hair over time, offering a reliable indicator of chronic stress. Samples were collected during two periods, separated by several months, to account for seasonal variations and ensure comprehensive data
The study's primary finding was the synchronization of cortisol levels between dogs and their owners. Specifically, dogs with owners exhibiting high cortisol levels also had elevated cortisol levels themselves, and vice versa. This pattern suggests that dogs may not only be affected by their immediate environment but also by the emotional states of their human companions.
Interestingly, the study found that the dogs' physical activity levels did not significantly impact their long-term cortisol concentrations. This contrasts with previous research indicating that short-term stress responses in dogs can be influenced by physical activity.
The lack of correlation between activity levels and long-term stress in this study underscores the complexity of factors contributing to chronic stress in dogs.
In conclusion, the 2017 study by Linköping University offers compelling evidence our best friends may mirror their owners' long-term stress levels. This discovery not only enhances our understanding of canine behavior and physiology but also underscores the profound impact humans have on their pets' emotional well-being.
