Millipedes

On my hike Saturday, I saw millipedes, their paddle-like legs flickering against the ground and pushing forward. The 6-inch creatures looked like miniature, brown freight trains snaking through a pass. I wondered how many legs they have. I know their name implies a thousand. But how many?

A millipede, curled for defense. Photo courtesy of the Petroglyph National Park.

It turns out each body segment has 4 legs. So, I found a millipede image and counted 75 segments. That's 300 legs on a 6-inch bug.

They curl up for defense, and extrude a nasty-tasting juice to discourage predators.

I see them usually after a rainstorm, like on Saturday. Normally, they spend daylight hours underground to keep cool and moist. We in the Chihuahuan Desert are in the monsoon season now (when we get half our yearly rainfall in the three months of July, August and September).

So millipedes crawl out in the cool after hours of a shower. They need water to eat and digest dead plants and animals that form their diet. Eating litter cleans the desert landscape, since things decay slowly in dry heat. Moreover, their excrement returns nutruents to the soil faster than the decay process does.

By the way, millipede ancestors were the first animals to walk on land about 420 million years ago. The ancient creatures were much bigger than their 6-inch descendants: six feet long and 18 inches wide (2 by 0.5 m).

For lingering questions:

Fossil millipede found to be the oldest land creature

Millipedes of Petroglyph