from Canada.com:


Victoria study with robo-dog shows lack of full tail limits communication
Nicholas Read , Canwest News Service
Published: Monday, March 24, 2008


Dock your dog's tail, and you run the risk of making it more aggressive. So say two University of Victoria scientists after observing how 492 real-life dogs reacted to a robotic dog with and without a docked tail.

UVic biologist Tom Reimchen and graduate student Steve Leaver wanted to find out what effect cutting off a dog's tail might have on its behaviour and the way other dogs behave around it.

What they discovered was that dogs will approach a dog with a docked tail more cautiously than they will a dog with a complete tail. And that, says Reimchen, could make the dog with a docked tail more aggressive.

"Think of it this way," he says. "What type of teenager would you get if everyone approached him saying, 'I don't trust you'? What type of personality would emerge from that? It could be the same in dogs."

These findings, based on a series of observations made in the summer of 2006, are published in the latest edition of Behaviour magazine, a European science journal dedicated to the study of animal and human behaviour.

Reimchen hypothesized that if a dog lacks a tail, arguably the most important communication tool it has when it comes to relating to other dogs, its behaviour could be negatively affected. To test that hypothesis, Leaver outfitted a toy dog with a motor in its hindquarters that would wag - or not - one of two artificial tails Leaver could attach to its rear end. The first tail was 30 centimetres long, roughly the length of a normal tail, and the second was nine centimetres, roughly the length of a docked tail.

Then Leaver took the robo-dog, which resembled a black lab, to a number of off-leash parks in the Victoria area to observe how real dogs reacted to it.
"When the long tail was wagging, then other dogs would approach (the robo-dog) in a confident friendly way," Leaver said in an interview. "But when the tail was still and upright, they were less likely to approach, and if they did, it was in a less confident way."

That, he said, was consistent with normal dog behaviour. In dog "language" a wagging tail usually means "come play with me," while a stiff, upright tail usually means "stay away" or at least "approach with care."

But when Leaver fixed the shorter tail to the toy dog, real dogs were more likely to believe that discretion was the better part of valour and approach it warily, Reimchen said, regardless of whether the shorter tail was wagging.

"Without a tail, whether it was wagging or not, it was closer to the situation where the [long] tail was upright and still," he said.

So, Reimchen surmises, if a puppy's tail is cut off when it's two or three days old, as is often done by breeders of such dogs as Doberman pinschers and Rottweilers for purely cosmetic reasons, it's possible that that puppy's experiences with other dogs will be affected for the rest of its life. And that could lead to the dog becoming more remote and aggressive.

"Our research does show a possible connection between losing that signal and losing the ability to communicate with a potential increase in aggression," he said.

A dog that lacks the ability to express its intentions with its tail may have to resort to other methods, Leaver says, such as growling, lunging or even biting. Or a dog that is always treated as if it were something to beware of, Reimchen says, may become a dog to beware of.

"It's not rocket science," he explained. "Suppose you have a group of 10 puppies, and two of them have their tails chopped off. If we look at those two puppies minute by minute, day by day, and how not being able to signal with their tails is going to affect them, my thinking is that this could lead to a personality that is more cautious and eventually more aggressive."

For opponents of tail docking, the UVic research is one more reason for Canada to follow the lead of Britain, several European nations and Australia and ban or at least limit the practice here.
Said Peter Fricker of the Vancouver Humane Society: "Tail docking is just cosmetic surgery and it's totally unnecessary. It can be a painful procedure and it removes one of the dog's key ways of communicating."