Playing fetch with a dog is a game that rings down the centuries - but the animal's behavior may go back much further, to before dogs even evolved. According to scientists at Stockholm University, the desire to fetch seems to be innate in some wolves.
Researchers at the university were studying the behavior of wolves when they discovered that some of the pups became interested in a ball and brought it to a person they had never met. This "shocked" the researchers, who had previously assumed that this game was introduced to dogs since being domesticated 15,000 years ago, after genetically diverging from wolves.
"When I saw the first wolf pups retrieving the ball, I literally got goosebumps," said university researcher Christina Hansen Wheat - who immediately wondered whether the desire to fetch might have helped bring humans and early dogs together.
"It was so unexpected, and I immediately knew that this meant that if variation in human-directed play behavior exists in wolves, this behavior could have been a potential target for early selective pressures exerted during dog domestication."
The researchers decided to test this hypothesis by raising three litters from when they were 10 days old. They then took them to a room one-on-one with a stranger, who threw a tennis ball to see if the wolf would return it.
The first two groups were uninterested, which didn't shock the researchers as they "never really expected wolf pups to catch on" to the game. However, the third group not only went after the balls, but also returned them to the stranger.
Researchers hypothesized that wolf pups' ability to play fetch might have been one of the reasons humans domesticated them (Credit: Stockholm University)
This is not the first time that researchers have discovered that a canine trait previously thought to have been created by human influence might actually have been present since before dogs evolved from wolves.
In 2017, scientists at Princeton University discovered a random genetic variation in wolves that may have caused them to socialize with humans. The researches raised 18 dogs and 10 wolves and treated them the same through their development.
To no-one's surprise, the dogs were far more sociable after the experiment than the wolves. However, the researchers discovered that the dogs had a disruption in a genome absent in the wolves, which may have contributed to their willingness to socialize.
The findings in Stockholm could strengthen the Princeton study's suggestion that animals were selected for domestication based on their ability to socialize with humans. Previous studies assumed that wolves were chosen based on their ability to understand gesture and voices.
"If early humans came into contact with a wolf that had a personality of being interested in them, and only lived with and bred those 'primitive dogs,' they would have exaggerated the trait of being social," said Bridgett vonHoldt, the Princeton study's lead author.
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