Dogs are entering a new stage of evolution, scientists discover

Service dogs are leading the way

It is thought dogs are going through a third wave of domestication driven by humans’ desire for pets that are friendly, calm and well-suited to a sedentary lifestyle.

Decades ago, dogs were regarded as working animals who hunted pests, herded livestock or guarded their owners’ homes. However, today owners seek dogs for companionship.

This shift has increased levels of a hormone responsible for social bonding in dogs, especially service dogs, scientists have found.

The hormone, oxytocin, is what drives dogs to seek contact with their owners. When humans first domesticated wolves, the canine’s sensitivity to oxytocin increased.

A study, conducted by researchers at Sweden's Linköping University in 2017, investigated how dogs developed their unique ability to work together with humans, including their willingness to 'ask for help' when faced with a difficult problem.

The researchers suspected that the hormone oxytocin was involved, as it is known to play a role in social relationships between individuals. 

The effect of the hormone is dependant on how well it binds to its receptors.

Previous studies have shown that variations in genetic material located close to the gene that codes for oxytocin receptors influences dogs' ability to communicate.

This means that a dog’s social skills are partially ingrained in their genetics.

Researchers observed 60 Golden Retrievers as they attempted to lift a lid off a jar of treats, which was intentionally made impossible to open.

Alongside this, they collected DNA swabs from inside the dogs’ noses to determine which variant of the oxytocin receptor each one had.

The dogs performed the test twice, once after receiving a dose of oxytocin nasal spray, and once after receiving a dose of neutral saline nasal spray.

The team then timed the dogs to see how long they would spend attempting to open the jar themselves before turning to their owner to ask for help. 

The results showed that dogs with a particular genetic variant of the receptor had a stronger reaction to the oxytocin spray than other dogs, and that the oxytocin dose made them more likely to ask for help than the saline dose. 

Canine experts Brian Hare and Vanessa Woods said that dogs’ behavioural traits are undergoing a third wave of domestication. 

As the role they play in our lives shifts from a worker to a companion, so has their behaviour and potentially their biology.

Hare is an evolutionary-anthropology professor at Duke University and the director of the Duke Canine Cognition Centre. Woods manages the centre’s Puppy Kindergarten program, which trains pups to become service dogs.

The Kindergarten also acts as a long-term research project to assess how different training strategies impact dogs' behaviour and cognitive development.

Writing in The Atlantic, the pair said that studying the puppies has convinced them that service dogs are 'uniquely well adapted to life in the 21st century’.

They said: “Unlike most pet dogs, service dogs are attracted to strangers, even as puppies.

“And increasing friendliness seems to have changed these dogs’ biology, just as it did thousands of years ago.”

While dogs used to spend much of their lives outside, they are much more likely to live indoors with their owners now.

They also interact with unfamiliar dogs and people more frequently. The pair believe that some behaviours that made dogs appealing to our ancestors have become maladaptive.

They said: “Dogs that are more energetic, excitable, fearful, or anxious than average are more likely to be relinquished to shelters, where they may struggle to find a new home.”

Woods and Hare believe that these new societal pressures are driving a third wave of canine domestication, with service dogs representing the most highly evolved members of the pack.