00:00Do animals laugh?
00:06People laugh together as a way to connect and bond.
00:10And though the sounds of laughter can vary widely across individuals and groups,
00:15the sound of a laugh is usually recognizable even between people belonging to different cultures.
00:23But what about animals other than humans?
00:27Do they produce sounds of enjoyment?
00:29And do these sounds, and what causes them, bear any resemblance to human laughter?
00:35In other words, do animals laugh?
00:42In humans, laughter can express a range of emotions,
00:46from positive feelings like enjoyment to negative ones such as disgust.
00:52People also laugh when they hear a joke, or when they see something that they think is funny.
00:59And while it's unknown if animals' intelligence includes what humans would call a sense of humor,
01:06many animals produce unique sounds during play, and researchers consider such vocalizations to be a close analog of human laughter.
01:16Recently, scientists reviewed dozens of studies looking for any mentions in any animal of vocal signaling during play,
01:24and they published their findings in the journal Bioacoustics.
01:29The researchers identified 63 mammal species and two bird species that laughed while playing.
01:36Many of these sounds, such as the purr of a vervet monkey,
01:42the ultrasonic trill of a rat,
01:46the whistle and squawk of a bottlenose dolphin,
01:50and the peeping of a squirrel monkey
01:54occurred only while the animals were at play.
01:58Scientists found these vocal play signals throughout the mammal literature,
02:03especially among primates, rodents, social carnivores,
02:08and, to a lesser extent, marine mammals, they wrote in the study.
02:13In fact, most primate species, including chimpanzees, gorillas, monkeys, and baboons,
02:19demonstrated playful laughter,
02:21from panting chuckles, lip-smacking and grunts,
02:24to cackles, trills, and squeals.
02:30And if you listen to the panting play laughter of primates,
02:33it's easy to see how our laughter may have originated during play.
02:39Human laughter may have started out as a similar panting sound
02:42that, over evolutionary time, became the vocalized ha-ha-ha that we use today.
02:54Laughing animals. Just another one of life's little mysteries.
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