Old dogs learn new tricks

For according to scientists, man's best friend is probably cleverer than you think.

Not only does Fido use different barks to communicate but he can even count.

Researchers at the University of California, Davis, US, recorded the barks of 10 dogs of six different breeds.

They believe individual dogs have different sounds for different situations.

A single high-pitched bark means, "Where has my owner gone?" while a lower-pitched harsher "superbark" says, "There's a stranger coming".

The idea that dogs can count is more controversial. A second study suggests dogs have a basic mathematical ability that enables them to work out when one pile of objects is bigger than another.

Doggie treats

Two researchers - Robert Young of the Pontifical Catholic University, Brazil, and Rebecca West of the University of Lincoln, UK - tested the idea with 11 mongrels and doggie treats.

The snacks were hidden behind a screen, and then shown to the dogs.

After the screen was lowered again, the researchers changed the number of treats or left them as they were, then let the dogs have another look.

According to a report in New Scientist magazine, the dogs stared for much longer at the treats if there were a different number from before.

The scientists think this is evidence that canines have some ability to count.

Pack mentality

This could have played an important role when dogs were wild animals, living in packs, says Dr Young.

"The dog evolved from the wolf only 12,000 years ago," he told the BBC.

"Wolves live in sophisticated social groups where knowing the number of allies and the number of enemies you have in a group would be very important in determining whether a behavioural strategy, for example trying to take over the group, would be successful or not."

Some researchers are sceptical, however. Erica Peachey, a consultant in animal behaviour, has seen no evidence so far that dogs can count.

She suggests that dogs' keen sense of smell might influence the results of the experiment.

"We forget that their senses are quite different from ours," she told BBC News Online.

"It raises huge questions if dogs are capable of that type of theoretical thinking."