Termites build castles in the air

Every “varmint” has its own way of building a home and some manner of protecting it from intruders and the elements. I see these beautiful and well built little castles on the Bosque Santa Lúcia trails every day but I never saw anything going in or out. I was suspicious that they were made by ants but a few years ago a biology professor at the Federal University of Pará told me that they are entrances to underground termite nests. My local community contacts can’t identify what lives below but they certainly have an explanation for the castle structure. It’s to keep water from draining into the hole. OK, I figured that one out, but they go a step further to say that the height of castle can be used to determine future rainfall. Higher structures indicate heavy rain; low-profile castles means less rain. My own guess is that the termites can build these castles very quickly.