I don't know...I read this and thought it was fun.
Hi Bill,
Why do we yawn? And why does it seem contagious?
--Sleepy Ruminator
Dear Sleepy Ruminator,
It's an age-old question, one that can keep you awake at night, and there is no exact answer. Near as we can tell, yawning is a way to signal others around us that we feel like getting some shuteye. But I've fallen asleep without yawning, and, of course, I've fallen asleep after my own virtual yawning festival, yawn after yawn. These observations lead me to believe that yawning sends a signal. As a kid, I heard that yawns are a means to get more oxygen or stretch certain facial muscles before sleeping. I'm skeptical of those explanations, because sleep and yawns are not always directly connected. If you're sleepy, you don't always yawn. If you need oxygen, you just breathe deeply.
Of course, yawning seems to be a very old form of behavior. It seems to be programmed deep in our brains. I've seen dogs yawn, and it makes me want to yawn right along with 'em. When your best canine friend is opening his jaws wide and shaking his shoulders, you can bet that he's not anxious to go outside and play or go for a long old walk. Modern wild dogs in Africa live in packs. They seldom stray off on their own. A yawn is a dog's way of telling her buddies in the dog pack (or you as her keeper) that she's ready for some doggie z's.
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Perhaps yawning was preserved in our brains from all the way back in ancient times. It may have been desirable for everyone in a tribe of humans (or other animals) to go to sleep at about the same time. That way, perhaps everyone in the tribe would be on the same sleep schedule, ready to take on the challenge of the next morning. Perhaps yawning developed in a tribe of nomads, people who wandered from camp to camp every few days. Getting up, packing, and setting off on a journey would require everyone to be working together at the same time. You wouldn't want any stragglers lagging behind the main group. They might get attacked or they might get just plain lost.
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You also wouldn't want a small group to go off on their own ahead of everyone else. They might get attacked, too, being a small number easy for an enemy to overcome. Or they might go off in some direction (the wrong way) the main tribe would rather avoid. If you're going to get lost, better to do it together. Tribes that didn't have this form of communication may have had discord, some arguing, and loss of efficiency. Their competitors, who did communicate this way, may have gotten a slight advantage.
I can imagine that the leader of an ancient tribe might have felt that it was time for everyone to hit the hay. If there was no hay to be found, perhaps he meant it was time to sprawl out on some rocks warmed by the fire, or a mat of pine boughs. So he yawned. Everyone else in the tribe yawned back, letting the leader know that they got the message: Time to put down the net weaving and sleep. Thousands of years after the last ice age, a yawn still sends the signal. Dogs yawn; we yawn. Dog packs sleep at the same time. So do humans in middle management meetings and lecture halls around the world. In those situations, perhaps our bodies are indicating that our time would be better spent resting rather than reviewing charts or chalkboard marks.
Hi Bill,
Why do we yawn? And why does it seem contagious?
--Sleepy Ruminator
Dear Sleepy Ruminator,
It's an age-old question, one that can keep you awake at night, and there is no exact answer. Near as we can tell, yawning is a way to signal others around us that we feel like getting some shuteye. But I've fallen asleep without yawning, and, of course, I've fallen asleep after my own virtual yawning festival, yawn after yawn. These observations lead me to believe that yawning sends a signal. As a kid, I heard that yawns are a means to get more oxygen or stretch certain facial muscles before sleeping. I'm skeptical of those explanations, because sleep and yawns are not always directly connected. If you're sleepy, you don't always yawn. If you need oxygen, you just breathe deeply.
Of course, yawning seems to be a very old form of behavior. It seems to be programmed deep in our brains. I've seen dogs yawn, and it makes me want to yawn right along with 'em. When your best canine friend is opening his jaws wide and shaking his shoulders, you can bet that he's not anxious to go outside and play or go for a long old walk. Modern wild dogs in Africa live in packs. They seldom stray off on their own. A yawn is a dog's way of telling her buddies in the dog pack (or you as her keeper) that she's ready for some doggie z's.
Love Science?
• Take a career quiz to see if science is for you
• Study science or engineering online
• Get help on science homework
Perhaps yawning was preserved in our brains from all the way back in ancient times. It may have been desirable for everyone in a tribe of humans (or other animals) to go to sleep at about the same time. That way, perhaps everyone in the tribe would be on the same sleep schedule, ready to take on the challenge of the next morning. Perhaps yawning developed in a tribe of nomads, people who wandered from camp to camp every few days. Getting up, packing, and setting off on a journey would require everyone to be working together at the same time. You wouldn't want any stragglers lagging behind the main group. They might get attacked or they might get just plain lost.
Ask Bill Nye
Got a question for the Science Guy?
Ask Bill Nye!
You also wouldn't want a small group to go off on their own ahead of everyone else. They might get attacked, too, being a small number easy for an enemy to overcome. Or they might go off in some direction (the wrong way) the main tribe would rather avoid. If you're going to get lost, better to do it together. Tribes that didn't have this form of communication may have had discord, some arguing, and loss of efficiency. Their competitors, who did communicate this way, may have gotten a slight advantage.
I can imagine that the leader of an ancient tribe might have felt that it was time for everyone to hit the hay. If there was no hay to be found, perhaps he meant it was time to sprawl out on some rocks warmed by the fire, or a mat of pine boughs. So he yawned. Everyone else in the tribe yawned back, letting the leader know that they got the message: Time to put down the net weaving and sleep. Thousands of years after the last ice age, a yawn still sends the signal. Dogs yawn; we yawn. Dog packs sleep at the same time. So do humans in middle management meetings and lecture halls around the world. In those situations, perhaps our bodies are indicating that our time would be better spent resting rather than reviewing charts or chalkboard marks.
