Some owners have suspected it for some time, but now has been confirmed by scientific research, which has shown that even dogs are able to take a deceptive behavior.
The study investigated whether dogs were able to mislead a human competitor in a choice situation. During training, the dogs had to deal with their cooperative owner, and with two strangers: one who acted cooperatively, giving food to the animal, and the other competitively, keeping food for themselves.
Dogs tended to drive the human competitor away from food when they thought the man would keep him for himself. Instead they happily brought their cooperative companion to their destination, knowing that they would receive some of the food.
During the test, the dog could lead one of these partners to one of the three positions where there could be food: one contained the preferred food product, a second a non-preferred food product and a third one was empty.
After leading one of the strangers, the dog could drive his cooperative owner to one of the stations. Therefore, the dog would have a direct advantage to deceive the competitive partner as it would then have another chance to receive the owner's favorite food. It is exactly what the animals have done, thus showing that dogs distinguish between cooperative or competitive behavior, adapting their behavior using deception as well.