Dec. 4, 2005 Researchers at the Spokane County Regional Animal Protection Service in Washington state say sometimes a bark is just a bark but a long, loud panting sound has real meaning. They say the long, loud pant is the sound of a dog laughing, and it has a direct impact on the behavior of other dogs. "What we found is that it had a calming or soothing effect on the dogs," said Patricia Simonet, an animal behaviorist in Spokane who has studied everything from hamster culture to elephant self-recognition. "Now, we actually really weren't expecting that." Nancy Hill, director of Spokane County Animal Protection, admits she was skeptical at first that this noise would affect the other dogs. "I thought: Laughing dogs?" Hill said. "A sound that we're gonna isolate and play in the shelter? I was a real skeptic until we played the recording here at the shelter." When they played the sound of a dog panting over the loudspeaker, the gaggle of dogs at the shelter kept right on barking. But when they played the dog version of laughing, all 15 barking dogs went quiet within about a minute. "It was a night-and-day difference," Hill said. "It was absolutely phenomenal." Officials say it works every time, and researchers across the country are taking note. "The laughing sound that they make is something that was not even considered a vocalization until this study was done," Simonet said.