People seem to love nothing more than anthropomorphizing our non-human counterparts in nature. These videos might make us giggle, but what about the creatures that star in them, can they laugh? The answer, according to a new paper studying animals at play, may be yes"to the tune of some 65 species that researchers pegged as "laughing" during bouts of playful activity, reports Mindy Weisberger for Live Science. "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," says Greg Bryant, a cognitive scientist at the University of California, Los Angeles and co-author of the study. Most of the 65 species identified by the study, which was published last month in the journal Bioacoustics, were mammals, such as primates, foxes, killer whales and seals, but three bird species also made the list. For animals, the researchers suggest, a laughing noise may help signal that roughhousing, or other behavior that might seem threatening, is all in good fun. "[Some actions] could be interpreted as aggression. The vocalization kind of helps to signal during that interaction that 'I'm not actually going to bite you in the neck. This is just going to be a mock bite,'" [said] Sarah Winkler ... the paper's lead author. "It helps the interaction not escalate into real aggression." Many of the animal laughs identified by the study sound nothing like a human chuckle. For example, Rocky Mountain elk emit a kind of squeal.