Dogs as intelligent as two-year-old children

Researchers have found that dogs are capable of understanding up to 250 words and gestures, can count up to five and can perform simple mathematical calculations.

Professor Coren, who presented his work on Saturday at the Annual Convention of the American Psychological Association, believes dogs are among the most intelligent animals and can rival apes and parrots for their ability to understand language.

Professor Coren said: "Dogs can tell that one plus one should equal two and not one or three."