Dogs only developed the capability to emotionally attach to humans after they were domesticated from wolves over 15,000 years ago – well, that’s the prevailing theory. Now, a Swedish study adds to a growing body of evidence questioning this hypothesis.
A research collaboration between Stockholm and Lund Universities has demonstrated that not only do wolves have the ability to develop social relationships with humans, but these behaviours are similar to those of domestic dogs raised in identical conditions.
12 dog and 10 wolf puppies were hand-raised by the same female human caregiver in a standardised and identical way. Then, researchers performed a “Strange Situation Test,” originally designed for testing attachment in human infants, on each of the animals. This essentially involved their familiar caregiver and a female stranger taking turns to come in and out of the room containing the dog or wolf.
The animal’s behaviour was then recorded and measured against several identified categories including positive or inquisitive behaviours such as exploration, physical contact, social play, greeting and actions more indicative of stress or fear, such as standing by the door, following, crouching, pacing or tucking of the tail.
Throughout the test, wolves demonstrated that they spent more time greeting and in physical contact with the familiar person than the stranger. This strongly suggests that, like dogs, wolves are more than capable of forming attachments to humans, and, as evidenced by the age of the animals, it is not a capability solely restricted to wolf puppies.
“It was very clear that the wolves, like the dogs, preferred the familiar person over the stranger,” said Dr Christina Hansen Wheat from Stockholm University in Sweden. “But what was perhaps even more interesting was that while the dogs were not particularly affected by the test situation, the wolves were and paced the test room.” When the familiar person re-entered the room, the pacing behaviour stopped, “indicating that the familiar person acted as a social stress buffer for the wolves”.
This is the first time this sort of attachment behaviour has been shown in wolves, and Hansen Wheat believes it “complements the existence of a strong bond between the animals and the familiar person”.
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Hansen Wheat suggests the ability for wolves to show attachment to humans makes sense when considering human-wolf interactions in prehistoric times. “Wolves showing human-directed attachment could have had a selective advantage and could have been a potential target for early selective pressures exerted during dog domestication,” she says.
The team hope to continue investigating and comparing the behaviours of dogs and wolves raised in identical circumstances, to contribute further to our growing understanding of the role domestication has played in our developing relationship with humankind’s best friend.