How did dogs become our best friends?

The cooperation between dogs and humans likely evolved from an original trait of their wolf ancestor. Photo / Getty Images

Man's best friend – a saying that refers to a long and loyal relationship with our canine companions. With huge variance among modern breeds, it's easy to forget that all dogs from chihuahuas to great danes descend from Canis lupus or the grey wolf.

New research shows that this cross-species cooperation is likely to be an original wolf trait that domesticated dogs have adapted over time to suit their more submissive personalities.

Humans are naturally social creatures and the success of our species would have been impossible without our ability to cooperate with each other to achieve a shared goal.
Other animals such as chimpanzees and elephants are also known to cooperate with each other and in some animals, this trait can transfer across different species such as with humans and dogs.

To try to understand the evolution of cooperation, scientists set up an experiment using wolves and domesticated dogs to try and figure out how far back this cross-species collaboration might go.

The researchers used 15 grey wolves and 12 mixed-breed dogs that had all been socialised with humans in the same way from an early age at the Wolf Science Centre in Austria.

The animals were given a task known as the loose string paradigm where two trays of food were placed on a table 10m apart and out of reach of the test subjects. The goal of the task was to bring the food within reach by simultaneously pulling on two lengths of loose string placed on opposite sides of the table. If only one end of the string was pulled, the string would come loose and the food stayed out of reach.

The test is said to help researchers understand whether animals understand the idea of cooperating and has previously been passed by chimpanzees, elephants and even keas.

For this study the activity was split into two formats: the first involved the animals arriving in the room slightly before the humans so that the animal could choose which side of the table it wanted to pull the string from. The second test involved the animal being released after the human had already decided which end of the string they were going to pull forcing the animal to coordinate with the human's decision instead.

The results published in the journal Scientific Reports found that both wolves and dogs were able to successfully complete the task even if it was the first time they had seen the equipment.

However, the wolves were much more dominant in their strategy for solving the problem and 14 out of the 15 wolves tried to steal the string from the human to enforce their preferred side of the table compared to only 2 of the 12 dogs.

Although both the wolves and dogs were highly successful in working with the humans to achieve the goal, the wolves were much more likely to initiate and start the task and have the human help whereas the dogs would wait for the human to start and then come in to offer aid.

The results suggest that rather than the cooperation between dogs and humans being introduced over time through living together, it likely evolved from an original trait of their wolf ancestor.

As submissive tendencies were selected during the domestication process, it seems that the partnership shifted from one of strong animal leadership to one of compliant cooperation, which avoided conflict.

So the next time you throw a ball for your dog in the park, be grateful that their evolved cooperative submissive nature means that they now bring it back to you rather than expect you to bring it back to them.