Termites build mounds up to 10 meters high one tiny particle of soil at a time. But a new study suggests that termites of the species Odontotermes obesus (pictured) are quite versatile, and may be able to use everything from wax to glass beads to construct mounds. Moisture is one of the key criteria for brick selection: If materials are too moist, termites are unable to crawl on them; if they are too dry, the insects cannot mix them with saliva. But even in this aspect, the termites are flexible: They can use red soil whose moisture content is anywhere in between 15% and 60%, the team reports this month in Scientific Reports. What’s more surprising is that the insects are able to handle brass, stainless steel, and other materials that they usually do not encounter in their natural habitat. For this reason, scientists think that brickmaking is a hard-wired behavior—in other words, give termites something they can move on and chew, and they’ll build a castle.