Dogs May Be Having The Last Laugh - On Us 8-1-1

Ever thought Fido knows something you don't? Could he even be laughing at you behind your back? It sounds like a joke, but the joke could be on you. Recent studies appear to have isolated the noise dogs make when they are amused or at play a sound which some researchers say mirrors the human laugh.

Nevada researcher Patricia Simonet of Sierra Nevada College in Lake Tahoe believes dogs make a specific noise during play that is distinctive from other sounds made during passive or aggressive confrontation. Simonet describes the sound as a breathy exhalation that sounds to a human ear like a dog's regular panting. However, when the frequency of the "laugh" was analysed, it was found to have a far broader range of frequencies than a regular pant.

As part of the investigation, Simonet noted the behaviour patterns of fifteen young dogs in an observation room. She broadcast recordings of the "laugh-pant" that she had taken earlier, and found the dogs reacted with excitement, often picking up a toy or approaching a presumed playmate, if another dog or human was in the room. Even Simonet's own attempts at emulating the sound prompted favourable reactions in the dogs, causing them to move towards her in a playful way, looking for a romp.

Laughing at play

Simonet is not the first researcher to theorise on the existence of animal laughter. Brian Knutson of the National Institutes of Health in Maryland has recorded sounds made by laboratory rats as they wrestle with one another. Apparently, the rats emit a distinct chirping noise when wrestling in a playful manner, a sound that they repeat before receiving morphine or having sex. Knutson suggests the sound is an expression of pleasure - one the rats make when they know they are to be rewarded.

Knutson's rat studies have significant implications for neuroscientists wanting to track the rodents' brains' reward circuitry. But he believes there is still some way to go before scientists can accurately measure how the rats' chirps compare to a guffaw or chuckle from a human.

Another analyst of rat chirps, Jaak Panskepp of Bowling Green University, Ohio, goes one step further to suggest laughter, at least in response to a direct physical stimulus such as tickling, may be a common trait shared by all mammals. In order to record the sounds rats made sounds of exceptionally high frequency Professor Panskepp placed a recording device in the cage with the rats in his study, and proceeded to tickle them gently around the nape of their necks. The rats soon began to emit their high-pitched squeak even at the sight of the recording device, as if in anticipation of being tickled. Panskepp noted, "the older animals do not chirp as much as the younger ones but they still like it a lot and they'll follow your hand around and get all excited. This emotional response that they're showing is quite a primitive form of laughter that maybe all mammals share."

Rats: Ticklish

Professor Robert R Provine also notes instances of perceived laughter in chimpanzees in his book Laughter: A Scientific Investigation. While studying the origins of the human laugh, Provine spent time tickling and playing with young chimpanzees at the Yerkes Regional Primate Center in Atlanta, Georgia. Provine discovered chimpanzees responded to pleasurable stimulus in the same way as dogs by emitting a breathy, panting sound.

The studies have many implications for scientists wanting to know more about how laughter is used as a form of communication, not only in animals, but ultimately in humans. The initial research notes that dogs usually restrict making their "laugh-pant" noise to when they are around other dogs. This would indicate the sound is a communication tool, allowing other dogs to pick up the mood of dogs around them. Like humans, animal laughter appears to be infectious, with all dogs seeming to respond to an initial burst of "dog laughter" with a mirrored sound of their own.

So the next time you're making a joke about Fido's canine antics, watch him closely. He could be having the last laugh.