Driving through the Australian countryside, we frequently see termite mounds. I’ve never seen one in the Americas, but they are common here.

A pamphlet explains that termite mounds “are built from soil brought from beneath the ground. The soil is cemented together with the insects' saliva and excreta.” (Take note 3M—Possible new adhesive: termite spit and poop.)

In the far north of the country, near Darwin, we saw the extraordinary thin slab-shaped mounds of magnetic termites.

In this hot, seasonally wet part of the continent, termites need protection from high temperatures and flooding. They avoid the latter by living in mounds above ground, but in so doing, they lose the ability to control temperatures that underground living would provide.

The tropical sun bakes termite mounds. Thin-skinned white termites cannot survive temperatures above 30º C, so these insects have come up with a high-tech solution. They build thin mounds with large flat sides aligned north-south to avoid heat buildup from solar energy.

(Maybe my notebook wouldn’t cook my lap had Apple engineers consulted with magnetic termites.)

Side and end views below illustrate the shape. The mounds in the photograph are about eight feet high.

To test the hypothesis that flat mound design enables termites to avoid high temperatures, experimenters rotated one of them a few degrees. A small angular misalignment caused temperatures inside the mound to rise to lethal levels. A north-south orientation was shown to be crucial.^*

But how do termites know where north is? The answer is they can sense the earth’s magnetic field, probably by storing magnetite in their bodies. Existence of their magnetic sensitivity was demonstrated by inserting strong magnets into an existing mound, whereupon the termites began rebuilding it in a different alignment.

Scientists found all this out and published it for my enlightenment and yours. But I suspect termites wish scientists would stop messing with their mounds and just leave them alone. If termites can wish, that is.

Different, less sophisticated termites built this really big mound. Brawn over brains.

Using my body as a measuring instrument (engineers like to measure things), I put the height at about three Smoots, or 16” 9”. Unlike the mounds we saw along the highway in more temperate regions, this one has fins. I wonder if the fins are involved in heat control as well?

So many mysteries, so little time.

* Note: Termite mound thermal management is actually way more complicated than the explanation I give here. If you are geeky enough to want the full story, check out this link.