Why do dogs wag their tails so much? Blame the owners
Humans bred canine companions with the trait because they like the rhythm, theory suggests
THE mystery of why dogs wag their tails has long fascinated humans. Now, scientists think it might be because their owners enjoy the rhythm.
A team of animal experts, including from the Max Planck Institute for psycholinguistics and the University of Rome, looked at existing research and found dogs wag their tails far more than other canines, such as wolves.
They suggest this could be down to two reasons: either tail-wagging is an inadvertent side effect of humans breeding dogs to be tame and docile, or humans deliberately bred dogs that wag their tails because we enjoy the rhythm.
Both suggestions are just theories, but they are the first to try to understand the evolutionary purpose of tail-wagging.
In the wild, the tail has a practical function as it helps swat away pests as well as improving balance, but domestication likely drove the increase in wagging prevalence, the scientists say.
“Changes in tail-wagging behaviour could have arisen as a by-product of a selection for another trait, such as tameness or friendliness toward humans,” the researchers write in their paper, published in Biology Letters.
A study published in 1999 bred 40 generations of foxes the same way as dogs, favouring domesticate traits. The foxes that were bred ended up behaving like dogs, including wagging their tails more, suggesting the genes associated with being tame and friendly could also be linked to increased tail wagging.
But the team said it was also possible that tail-wagging was a central goal of domestication, rather than an unintended consuquence.
The team said: “Tail-wagging behaviour may have been one target of the domestication process, with humans (un)consciously selecting dogs who wagged their tails more often, and potentially more rhythmically.”
They added: “Propensity for rhythms could have driven human selection for the conspicuous rhythmic wagging of the tail in dogs, and could explain why dogs exhibit it so often in human-dog interactions.”
Both the theories explain why some breeds are more exuberant waggers than others, the researchers said.
“Under both hypotheses, selection on tail-wagging behaviour may not have been uniform across breeds; for example, hunting-type dogs wag their tails more than shepherd-type dogs, and have also experienced different selective pressures throughout domestication,” they said.
“Targeted tail wagging research can be a window into both canine ethology and the evolutionary history of characteristic human traits, such as our ability to perceive and produce rhythmic behaviours,” the team said.