Those of you interested in animal behaviour, may find this interesting.
'Here boy' makes dogs wag to the right
*Direction of tail wagging highlights different tasks of brain halves.*
Dogs wag their tails to the right when they see something they want to
approach, and to the left when confronted with something they want to
back away from, say researchers in Italy. The finding provides another
example of how the right and left halves of the brain do different jobs
in controlling emotions.
Unfortunately, because dogs move about so much, the bias can only be
detected using video analysis. It's not obvious enough for you to tell
whether the next dog you encounter is going to lick your face or turn tail.
"After discovering this, I look at every dog I meet, but my impression
is that this is difficult to check outside the lab," says psychologist
Giorgio Vallortigara of the University of Trieste. But it could be used
in animal welfare, he suggests, to help gauge an animal's state of mind.
Vallortigara and his colleagues tested 30 pet dogs of varying breeds,
recruited through an obedience school at the University of Bari's
Over a series of trials, they videoed each dog's response to being shown
either their owner, a human stranger, a cat, or a Belgian shepherd
malinois, a large dog breed similar to a German shepherd.
Shown a human or a cat, tails wagged consistently to the right. The
unfamiliar person elicited less wagging than the owner, and the cat the
least wagging of all --- probably because the dog was so interested in
giving chase that it was distracted from wagging, says Vallortigara.
Shown a large, unfamiliar and intimidating dog, the dogs wagged their
tails more to the left. Dogs also wagged to the left when left on their
own without anyone to look at, the researchers report in /Current
Biology/^1 <http> .
Previous studies have shown that, in humans, strong activity in the
brain's left hemisphere (which controls the right side of the body) is
associated generally with a sunny disposition. Human studies have also
linked left-brain activity with approach behaviour, and right-brain
activity with retreat.
Dogs are already known to favour one paw over the other --- most male
dogs are left-pawed, whereas females show a weaker tendency to
right-pawedness. But what they do with their tails may be a better guide
to how their brains work, says Vallortigara.
"The use of forelimbs is not so important in animals other than humans,"
he says. "But tail wagging is an important emotional response."
"This is a fascinating way to measure lateralization," says
neuroscientist Lesley Rogers of the University of New England in
Armidale, Australia. "It will be valuable in a range of tests, not only
in dogs, but in other species with tails."
Biases for right- or left-'handed' behaviours have been seen in fish,
amphibians, reptiles, birds, reptiles and mammals. "The evidence is that
brain asymmetry is quite ancient," says Vallortigara. "It seems to have
started early in the vertebrates."
Parcelling out tasks to one side of the brain or the other avoids
duplication, and may help decision-making by reducing conflict between
More puzzling, says Rogers, is why such biases also arise in behaviours
such as escape. Toads and chicks, for example, are both more likely to
leap away from something seen in the left eye --- suggesting that a
predator could learn to sneak up from the right. Why such biases do not
vary at random from animal to animal is still uncertain.
Vallortigara's team next aims to see whether a dog's retreat or approach
response depends on which eye or nostril is stimulated by a friend or foe.
They Say You Can't Buy Love......But You Can, You Can Buy a Dog.