More to a dog than tricks

In 40 tests Rico got it right 37 times, demonstrating he had a vocabulary comparable to dolphins, apes, sea lions and parrots that have undergone extensive training.

The researchers then repeated the test. This time they put seven of Rico's toys in the other room along with one toy he had never seen. His owner called out the unfamiliar name of the new toy.

Rico correctly retrieved the new item seven out of ten times. Rico demonstrated, at least on those tests, that he could perform simple logic.

This feat suggests that dog owners, who claim their pets understand what their masters are saying and are trying to respond, may be right.

Yet we have to be careful about findings such as this. At the turn of the 20^th century a horse named Clever Hans that supposedly could add and subtract became infamous when researchers showed the stallion was really just responding to subtle cues from his owner.

Researchers have replicated Rico's success in a number of other dogs but if you try this at home with your pooch, you may be disappointed. It appears that the experiment only works in a small minority of canines.

Even so, this research poses some interesting questions. Can dogs distinguish between accidental and intentional actions? Does a dog understand that a picture is both an object, and an object that refers to another object?

Researchers in the US and Europe are currently putting our four legged friends through these tests to try and find the answers.

If a dog can understand that a picture of a bone is just a picture, then we are one step closer to being really able to, as Doctor Doolittle sang, 'talk to the animals' – or at least the domestic dog.