From A Recent Study - At Least 65 Species Of Animals Laugh

Many people were surprised when they saw Max laugh! I have seen my Max laugh almost everyday. I miss his smile and his kisses. 

This is a slap in the face of sapiens who look down on animals. Another reason to treat our fellow non-human animals. 

Researchers at UCLA have identified 65 species of animals who make "play vocalizations," or what we would consider laughter. Some of those vocalizations were already well documented—we've known for a while that apes and rats laugh—but others may come as a surprise. Along with a long list of primate species, domestic cows and dogs, foxes, seals, mongooses and three bird species are prone to laughter as well. (Many bird species can mimic human laughter, but that's not the same as making their own play vocalizations.)

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The UCLA researchers shared that the study of laughter in animals can help us better understand our own evolutionary behavior.

“This work lays out nicely how a phenomenon once thought to be particularly human turns out to be closely tied to behavior shared with species separated from humans by tens of millions of years,” Bryant said, according to UCLA.

“When we laugh, we are often providing information to others that we are having fun and also inviting others to join,” Winkler said. “Some scholars have suggested that this kind of vocal behavior is shared across many animals who play, and as such, laughter is our human version of an evolutionarily old vocal play signal.”

I knew about Rat's laughter since Max was a puppy. 

And we treat them horrible with animal testing. Wake up humans!