Binnick's Languages and Linguistics Blog

Tardigrades, also known as water bears and other cute names, are some of the most extraordinary animals on earth. They are a fraction of a millimeter in length and look like stuffed pillows with eight clawed feet. And the thing about them is they are just about impossible to kill.

The NSF says,

Measuring less than half a millimeter long, tardigrades — also known as water bears — can survive being completely dried out; being frozen to just above absolute zero (about minus 458 degrees Fahrenheit, when all molecular motion stops); heated to more than 300 degrees Fahrenheit; irradiated several thousand times….

I was reading an article about their immunity to harm today and ran into this passage:

The team devised several experiments to temporarily expose water bears to stress-inducing, free-radical-producing conditions, such as high levels of salt, sugar and hydrogen peroxide. Under these forms of stress, tardigrades curl up into a temporary, protective state of dormancy called a tun. The researchers monitored the conditions in which the tardigrades hunkered down and found that free radicals did seem to induce the tun state, although the mechanism was not yet clear.

A tun is a kind of cask, and a tundish is a funnel. And we all know about tons and tonnes.

So what gives with this “tun” state?

Britannica’s article in the tardigrade confirms this term:

…suspended animation called the “tun” state—in which the body dries out and appears as a lifeless ball (or tun). In this state their metabolism may decline to as little as 0.01 percent of its normal rate. Tardigrades can survive as tuns for years, or even decades, to wait out…

And National Geographic specifies the tun state as being like a dried ball:

Without access to water, a tardigrade will curl up into a dry ball called a tun. Their body systems slow down so much that they’re almost—but not quite—dead. The tiny animals can survive like this for decades. Scientists call this extreme type of hibernation “cryptobiosis.”

Finally, to find out why this is called the “tun” state, I did what no self-respecting researcher ever does: I asked a chat bot. This is what it said:

The term “tun” actually originates from an Old English word meaning “cask” or “barrel,” which refers to a large container typically used for storing liquids. In the context of tardigrades, the term “tun” was likely chosen because the dehydrated, shriveled-up state resembles a small barrel or container, reflecting the protective nature of this form against harsh environmental conditions.

I don’t buy this account, but it makes some sort of sense. I’d like to know who came up with the term and how.