Back in June, when I had my ants in their little wood-box setup, I observed an odd behavior that I couldn't quite figure out. In the box, I had wet paper towel that I used to provide water for the ants. I started with a clean paper towel and after a day or so, the paper towel was covered with a bunch of dirt. Not enough to cover it all up, but enough to let you know that the ants were up to something.

Here's a picture, for you visual people. Again - this picture was from back in June; my ants are no longer in these wood containers.



I wrote up a couple of theories on it on that page, but none of them were entirely satisfactory.

Last night, I think I *might* have stumbled on a clue that brings me closer to solving the mystery.

I caught a very large moth that was hanging outside my front door against the wall, and as I do with all of my ants' food, I squished it in a napkin and placed it on the ants food area. Unlike crane flies, moths are quite full of bug-guts, so when I squished it, the moth's innards spewed out, leaving a small glop of moth-sludge dangling from the carcass. I wondered how the ants were going to deal with the moth guts.

A few hours later, I went to the terrarium to see what was up, and to my surprise, the ants had covered the moth guts up with dirt. They were doing what they could to pick pieces off the huge moth (possible too large for them to move), and also covering the guts up with tiny dirt clods.

This also reminded me that a few days after I moved my ants into their current habitat (in the horizontal position), a poured a tiny bit of sugar on their Plexiglas tray. The next day, the sugar was completely liquified (humidity? or did the ants do it?), and a day later, the liquid sugar was completely covered with dirt.

New theories:

1. My ants hate messes, and cover up liquid messes with dirt. This would be a useful survival behavior, as they live in Washington where it rains frequently; plugging up sources of water may protect their tunnels.

2. My ants prefer to transport liquid via clods of dirt, as it's easier to move around.

I'll have to figure out a way to test these theories and come to a conclusion. I've never read anything on this sort of thing, so I'm fascinated by it and I'm looking forward to discovering the results.

Update: I e-mailed Myrm with the question, and this was his reply:

Many ants species do as you have described. My Tetramorium always bury their food under mounds of soil which they then go back to at times, open up the top of the mound and eat some of the food. When they have finished they cover it back up and save it for later. Ants also cover up water/honey to allow it to soak into the dirt granules which then makes carrying it to the nest a lot easier.

So I guess my theory #2 was correct. Good to know.