You’ve seen it happen. You’re lounging on the couch, your dog lets out a dramatic, jaw-cracking yawn, and before you know it, you’re doing the same. What is this mysterious, contagious urge? Is it just a shared moment of boredom? As it turns out, the yawn is a biological marvel, a social cue, and for some animals, a surprisingly aggressive statement.
Let’s dive into the weird, wonderful world of the animal yawns.
Why We Can’t Stop The Gape
That moment you “catch” a yawn from a friend is a real phenomenon. Scientists call it echophenomena: the hardwired human (and animal!) tendency to mimic each other’s actions. A 2017 study in Current Biology found that contagious yawning isn’t just for humans, as chimps and dogs get it too. We’re all just a bunch of copycats.
Here’s the fun part: The study also found that the more you try to resist a yawn, the more you want to do it. It’s like telling your brain, “Do not think about yawning,” which is basically an invitation for it to think of nothing else. So, next time you’re in a meeting and someone lets out a big one, don’t fight it. Just surrender to the science and let it rip.
So, What’s A Yawn For, Anyway?
It’s more than just a sign of being tired. Scientists have a few theories:
Brain Coolant:
This is the most widely accepted theory. Yawns bring a rush of cool air into our lungs and circulate cooler blood to our brains, helping to maintain an optimal temperature. One experiment showed that when people applied a cold pack to their neck, their need to yawn dropped dramatically. Think of it as a built-in air conditioner for your head.
The Wake-Up Call:
Yawns aren’t just for sleepiness; they’re also a way to prime you for a moment of attention. They can help shake off a sluggish feeling and boost alertness when you’re bored or tired.
Social Glue:
While yawning might be a biological function, it’s also a powerful social tool. Dogs will “catch” yawns from their owners, but only if they know them well, suggesting it’s a form of emotional attunement. Wolves in a pack and lions in a pride often yawn in sync, a sign of their close social bonds. It’s like a silent, shared signal that says, “I’m with you.”
The Big Brains Yawn Longer
Who yawns the longest? Us. A team of “yawnologists” (yes, that’s a real thing) studied the yawn timings of various mammals from YouTube videos. The findings, published in Biology Letters, revealed a striking correlation: animals with bigger brains yawn for longer periods.
Yawn duration was strongly linked to three things: brain weight, total number of neurons and number of neurons in the cerebral cortex (the ‘thinking’ part of the brain).
Species with more neurons and more complex brains yawned longer. Those with simpler brains, like birds and rodents, had much shorter yawns. The connection held across mammals and birds, and even when body size was factored in, the brain still came out as the best predictor. So it’s not about being big. It’s about being brainy!
While a hippo’s yawn looks epic, it only lasts a few seconds. An African elephant’s yawn clocks in at about 3-4 seconds. But humans? We are the champions of the long haul yawn, averaging just over six seconds. We’ve officially mastered the art of the dramatic gape.
Not All Yawns Are Created Equal
The simple act of yawning has wildly different meanings across the animal kingdom.
Don’t be fooled by a smiling crocodile! A crocodile’s dramatic yawn is not a sign of fatigue; it’s a territorial display. It’s basically a toothy way of saying, “This is my swamp, and these are my very sharp teeth.”
Pelicans take yawning to a whole new level. When they yawn, it’s not just a polite gape; it’s an epic unhinging full face flip! They flip their entire throat pouch inside out, likely to stretch and realign their jaws after swallowing a massive fish.
A snake‘s yawn is often post-meal, stretching their jaws back into place after swallowing something ridiculously large. It’s less of a yawn and more of a “my mouth needs to be put back together now, please.”
Is it a social signal or a warning? That depends entirely on the species and probably the mood. Gelada Baboons use yawning in two very different ways: males use it to flex dominance (complete with gum-flashing and dramatic flair), while females yawn more gently to strengthen social bonds. Probably a good idea to figure out which one you’re seeing before you yawn back!
Penguins, on the other hand, work yawns into their courtship rituals. They tilt their heads upward, stretch their beaks wide, and look like they’re auditioning for a slow-motion opera. It’s not an “OMG” moment. It’s foreplay.
In more aggressive animals like Siamese fighting fish, a yawn can be a clear warning. It’s saying ‘back off!’
So, the next time you find yourself caught in a contagious yawn loop, just remember: you’re not just tired. Your brain is getting a quick refresh, you’re sharing a moment of social connection, and you’re proving that humans are the undisputed champions of the long haul gape.
And if someone catches you yawning, don’t apologise. Tell them your highly evolved, neuron-packed brain is merely doing a bit of internal temperature control.
And I bet you’ve already yawned twice while reading this!
References:
University of Nottingham. (2017, August 31). Yawning: Why is it so contagious and why should it matter? ScienceDaily. www.sciencedaily.com/releases/2017/08/170831123031.htm
Massen et al. (2021). Brain size and yawn duration across species. Communications Biology pubmed.ncbi.nlm.nih.gov/33958700
Gupta & Mittal, (2013). Yawning and its physiological significance. pmc.ncbi.nlm.nih.gov/articles/PMC3678674
Ramirez et al. (2019). Manipulating neck temperature alters contagious yawning in humans. Physiology & Behavior. doi.org/10.1016/j.physbeh.2019.04.016
Fox, A. (2021, April 7). Contagious yawning may keep lion prides in sync. Smithsonian Magazine. From: www.smithsonianmag.com/smart-news/contagious-yawning-may-help-prides-lions-sync-180977429
