Half Measures Can Save Lives
In the Scribes Series, there is a type of sapient being that has four brains. If you want to know more about that, please read the books–I don’t want to spoil anything here. But I recently learned about animal brains in our world that are almost as strange. Those of dolphins, for example.
Wait, what’s so weird about dolphin brains? Questions like that are why you read these articles.
Imagine having lungs that stopped working when you sleep. (Even without having sleep apnea, I mean.) That’s what life is like for dolphins. Lacking gills, they swim to the surface two to seven times a minute to breathe through a blowhole. This is a conscious act–one they can’t do while asleep. That means they have to be awake all the time, right? Well, kind of.
For about eight hours a day, one side of their brain sleeps while the other is awake. They swap sides every few hours. The side that’s awake keeps the dolphin moving and breathing. This is called unihemispheric sleep. While the left hemisphere of their brain is sleeping, their right eye closes, and vice versa. That’s because the nerves cross over–a feature called decussation. I tried really hard to fit in a cussing joke here, but I got nothing. Anyhow, in cold water, this ability to stay moving near the surface helps keep dolphins warm.
The overachievers among you are jealous now. I could get much more done if I could have only half of my brain sleep at a time. What if dolphins went to school and attended lectures. Would their teachers scold the students for being half-asleep? Maybe the teachers themselves are half-asleep while lecturing.
Strange as this is, dolphins aren’t alone. Whales, manatees, seals, and some birds do the same thing. In fact, some birds can switch between half-sleep and full sleep, depending on their needs. If mallard ducks are clustered together, the ones at the fringes are tasked with watching for predators. They usually fall into half-sleep with their open eye facing out. The birds nestled in the middle of the group are free to fall into full sleep.
Imagine being so afraid that you literally have to sleep with one eye open.
Some birds go on long migratory flights without stopping because they use half-sleep in midair. Some can even take 10-second full naps while gliding on strong winds. Once they land at their destination, they can finally enjoy full, bihemispheric sleep.
Alligators and Crocodiles are thought to be unihemispheric sleepers, too, but no scientist has managed to take the EEG readings of their brain activity to confirm this. I suppose capturing one of these creatures and carting it off to your lab isn’t exactly the easiest thing to do. If you happen to pull this off and get readings, please share them with me. (And the rest of the science world–they’d like to know, too.) Not that I’m daring anyone to do this. I don’t carry enough liability insurance for all that. 
That’s all I have for you. It’s a short one, for a change. And, I have a confession–I was only half awake while writing this article. Now it’s time to get bihemispheric sleep.
Later Edit: the night after writing this article, I got absolutely no sleep in either of my brain hemispheres. I laid awake in bed all night, and I don’t even have a valid excuse, like watching for predators or swimming to the surface to breathe.
Writing update: I’m done outlining episode 4 and a quarter of the way through the first draft.
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