Your pet dog has clear conscience too

That man's best friend has struck an emotional chord with you is what every owner will agree without even thinking about it for a moment. Now researchers have scientific proof that your canine -- and probably many other animals -- have a conscience too.

According to lead researcher Roberto Cazzolla Gatti, till now only humans and great apes (gorillas excluded), a single Asian elephant, some dolphins, Eurasian magpies, and some ants have passed the test of mirror self-recognition (MSR).

A wide range of species has been observed to fail the test, including several species of monkeys, giant pandas, sea lions, birds and dogs.

Dogs, in particular, show no interest in looking in the mirror, but usually sniff or urinate around it.

"Dogs and wolves, like dolphins, show a high level of cognitive complexity, but previous attempts to demonstrate self-recognition in these animals have been inconclusive," Gatti said.

He devised a new test and called it the "sniff test of self-recognition (STSR)".

"This test provides significant evidence of self-awareness in dogs and can play a crucial role in showing that this capacity is not a specific feature of humans and a few other animals," the study noted.

The research was conducted with a test performed on four dogs -- all strays who grew up in semi-freedom.

Gatti collected urine samples from each dog and divided and stored them in containers labelled to each dog.

Then he submitted the animals to the sniff test of self-recognition.

He placed within a fence five urine samples containing the scent of each of the four dogs and a "blank sample", filled only with odourless cotton wool.

The containers were then opened and each dog was individually introduced to the inside of the cage and allowed to freely move for five minutes.

The result was surprising: all dogs devoted more time to smell the urine samples of the others rather than their own.

"This behaviour confirmed the hypothesis that dogs seem to know their own smell exactly, they are less interested in their own and they are, therefore, self-aware," Gatti informed.

In addition, the study shows a correlation between the age of the individual dogs and the time spent to sniff the urine samples.

"It strongly supports the idea that self-awareness increases with age, as demonstrated in other species, such as chimpanzees and humans," the findings showed.

The article has been published in the journal Ethology, Ecology and Evolution.