If New Zealand kea ever start producing sitcoms, they’d probably be wise to include a laugh track.
A team of European scientists has found that a playful mood can spread between the mountain parrots much as it does between humans, according to a paper published Monday in Current Biology. Previously, scientists had only observed this social phenomenon in mammals.
Renowned for their smarts, the world’s only alpine parrot is no slouch when it comes to play. Their insatiable curiosity compels them to peck car windshields and carry off anything that isn’t nailed down, much to the frustration of unsuspecting tourists.
It was just this kind of intriguing behavior that attracted the attention of a team of scientists from the University of Veterinary Medicine in Vienna, Austria. They wondered if the kea’s playful behavior could be elicited by the laughter-like calls the birds make while fooling around.
To test their hypothesis, they played their own hidden-camera prank on the avian tricksters. Taping wild kea behavior for 15 minutes at a time, the researchers played audio recordings (including a kea laugh, a regular kea call, a different bird call, a whistle, and a neutral digital tone) during the five-minute middle interval.
The high-pitched cackle of the kea warble hit the birds like the end-of-school-bell affects weary youngsters. Compared with the other sounds, the scientists observed individuals become dozens of times more likely to engage in “play events” such as wrestling, playing catch, aerial acrobatics, and mid-air footsie. They tended to play each game dozens of times longer as well.
Most intriguingly, the laugh track had a near-universal effect on the birds. “Kea of all ages, including adult males and females,” became more likely to frolic after hearing the recording, the team wrote in the paper.
While it’s impossible to know precisely what was going on inside the keas’ heads, the researchers emphasized the fact that this call seemed to be able to cause bouts of play to break out. Rather than joining birds already mid-game, the recording led kea to start new games together, or even alone.
“These instances suggest that kea weren’t ‘invited’ to play, but that this specific call induced playfulness, supporting the hypothesis that play vocalizations can act as a positive emotional contagion,” they wrote.
In other words, their laughter is infectious. It’s a phenomenon familiar to anyone who’s noticed that comedy movies are funnier with friends, as well as stand-up comics who get to follow a riotous act. Scientists have seen similar behavior in mammals, but the study is a first for birds.
“The only other animals to show this contagion effect are chimpanzees and rats, both very or relatively close in evolutionary terms,” lead author Raoul Schwing told New Scientist. “Our finding further bridges the perceived gap between humans and animals, and shows that it also happens in birds, which are very distantly related.”
The study continues the long tradition of showing us how much we have in common with other species. “If animals can laugh,” Dr. Schwing said to New Scientist, “we are not so different from them.”