I took a walk along the river the other day. I wasn’t paying much attention and was just enjoying the day when I saw the first millipede. It was right in the middle of the road, moving north.

Millipedes are harmless little arthropods that belong to the class Diplopoda, which translates as “double leg”. The term “millipede” translates as 1,000 legs. They have closer to 100 legs but “centipede” was already taken. Centipedes, which belong to the class Chilopoda, are also poorly named because rarely do they have more than 30 legs.

A little further along my walk was another millipede. It too was in the middle of the road and headed north. Again, I noted the millipede but didn’t think too much about it and continued my walk.

I see millipedes quite often in the garden and at this time of year, in our basement. They are small and harmless. Some species of millipedes do get quite large and the desert millipede gives off hydrogen cyanide gas, which not only smells bad, it can be deadly for small animals. I once spent a month in the Sonoran Desert studying everything from rattlesnakes to pine tip moths. To create an insect kill-jar I caught some desert millipedes and placed them in a jar. I then put a wad of cloth over them and would put butterflies and moths in the jar and close the lid. It didn’t take long for the butterflies and moths to die and I would then take them out and pin them for the collection.

It was when I saw my third millipede in the middle of the road and headed north that my interest was piqued. What were these millipedes doing? As I walked I counted a fourth, then a fifth. All were in the middle of the road headed north. To the south was a harvested cornfield, to the north the river. My guess was that the millipedes, which feed on dead plant material, had been living in the cornfield all summer long and now that winter was coming they were headed to the river bottom to burrow down in the leaf litter below the trees - a fall migration of sorts.

The further my walk took me the more millipedes I saw. I was convinced that I was watching a migration and that their migration from the field to the river bottom was just as amazing as the migration of sandhill cranes or robins. Then a wrench was thrown into my thoughts. A millipede was moving south! “Where are you going, dude?” I actually said out loud. “The river’s that way” and I pointed north as if the millipede would see and hear me. I figured he was lost. Later another millipede was headed south. Then another. My hypothesis of a migration was falling apart. By the time I got to the pickup I had counted five southbound millipedes and 20 northbound. I still think it was a migration but the “southbound-five”, as I call them, still have me puzzled. Where the heck were they going?