We know when our dogs are happy, sad or frightened,
but do they laugh?
Charles Darwin, father of the theory of the evolution, once tackled this question in his book, The Expression of the Emotions in Man and Animals, published in 1872.
He noted that "the upper lip during the act of grinning is retracted, as in snarling, so that the canines are exposed ... but the general appearance of the animal clearly shows that anger is not felt." He concluded that though some people "speak of the grin as a smile," he personally could never verify that claim, much less actual laughter.
There is always a risk in anthropomorphizing emotions – that is, giving our pets human characteristics. For instance, it's a mistake to assume that your dog's guilty look is in response to knocking over a priceless vase.
He has no idea he did anything wrong five minutes after the fact; he just knows you're angry and is desperate to appease you, the pack leader.
But a researcher in Nevada believes she has found a method to prove that the breathy exhalations dogs make during play are a type of laughter. Her results were presented last summer at a meeting of the Animal Behavior Society. Patricia Simonet and a team of researchers recorded dog sounds in dog parks from a distance using parabolic microphones.
The breathy excited pants were later played in an observation room. The sounds elicited play; dogs picked up a toy and trotted over to a person or another dog (depending who was in the room). The breathy exhalation was found to have a different frequency than regular panting from exertion. Dogs have much more sensitive hearing than people, so it is theorized that they pick up on the difference and respond to it.
However, whether dogs actually "laugh" is still unknown. For the average pet owner, however, the question is academic. The joyous glint in a dog's eyes, the enthusiastic play bow and the happy bark all communicate the most important thing: "I am having fun!"