An unspoken bond of understanding exists between a dog and its owner and is unlike anything else in the natural world, scientists have found.
A study has proved that dogs are genuinely in tune with human emotions, feelings and movements in a way no other species can mirror and have this ability at birth.
The only attributable explanation, researchers say, is the development of a unique bond between the two species carved from more than 10,000 years of domestication.
Scientists have long studied the relationship between humans and man's best friend but are still unravelling how we turned a fierce predator into a docile companion animal.
A new study from Duke University in North Carolina looked at the difference in behaviour between wolf puppies and infant dogs. A total of 88 animals – 44 dogs and 37 wolves – were enrolled in a study, with none of the animals older than 18 weeks.
Wolf pups in the study were from the Wildlife Science Centre in Minnesota and were hand raised by people. Keepers fed the wolves by hand and spent 24 hours a day with them. In contrast, the dogs were left in their litter with their siblings and mother and had minimal contact with people.
All the canines, dogs and wolves alike, underwent the same tests to determine how they responded to human clues and behaviour.
In the experiments, researchers hid a treat in one of two bowls and gave the participating puppy a clue to help them find the food. The gesture varied by trial, including a pointed finger, a glance in the direction of the food and putting a small wooden block next to the correct bowl – a practice foreign to the animals.
Analysis of the results revealed dog puppies, despite having minimal prior experience with people, understood where to go with ease and were twice as likely to get it right as wolf puppies of the same age who had spent far more time around people.
Seventeen of the 31 dogs consistently went to the right bowl, whereas none of the wolves performed better than random chance. Most of the dogs were able to pick up and follow clues from a person, whereas human tips were completely foreign to all the wolves.
The researchers also report that domestic dogs went to the right bowl at the first time of asking, proving they are born with this skill and need no training in order to comprehend human instructions.
The finding backs up a recent study from the University of Arizona, which studied 375 eight-week-old puppies, and concluded they are able to communicate with people from birth and need no training or practice to understand what their owner is saying.
"Dogs are born with this innate ability to understand that we're communicating with them and we're trying to cooperate with them," said study author Hannah Salomons, a doctoral student at Duke University.
Exactly how humans and dogs came to live in harmony remains unknown, with various theories touted as possible explanations.
However, Professor Brian Hare, the senior author on the study, said the research findings are strong evidence to back up the "domestication hypothesis", which says ancient hunter-gatherers living more than 12,000 years ago encountered wolves in the wild and tribes allowed some of the wolves to eat the leftovers of their kills.
But only the most timid of the predators were tolerated, and this meant that over generations only the most docile, human-friendly wolves got food and reproduced. Eventually, a lineage of wolves emerged which were tuned into human behaviour and the two species slowly became closer and more co-dependent.
This relationship led to men and dogs eventually hunting in tandem, working as a pair and living together. Now, many dog species work as service animals and assist fire crews, guide the blind and rescue stranded people.
"It is something they are really born prepared to do," said Professor Hare. "This study really solidifies the evidence that the social genius of dogs is a product of domestication."
The study is published in the journal Current Biology.