Wild About Texas: Texas striped millipede has unique defense system

To the general laymen, anything with more legs than their beloved house cats or dogs are nothing more than just “bugs.”

But in reality, there is so much more to those creatures that have more than four legs. In fact, here in west Texas, there is a species of arthropod whose common name refers to the amount of legs that it possesses, and that animal is the Texas striped millipede.

Millipedes belong to a class of arthropods known as Diplopoda, and this class, with more than 140 families, is the largest class of the arthropod group known as myriapods.

An astounding 12,000 recorded species of millipedes have been described worldwide, and this arthropod class can be observed on every continent, with the exception of Antarctica.

In West Texas, the most widely spotted variety is the Texas striped millipede (Orthoporus ornatus).

Texas striped millipedes, like all arthropods, are invertebrates, meaning they do not have a backbone.

Instead, their skeletal structure is based on the hard “shell-like” exoskeleton, which provides them with a limited amount of protection.

Their body is segmented, and each section has two pairs of legs.

The name millipede can be translated as “1,000 legs,” however, since they typically have between 30 and 40 body segments –120 to 160 legs— this designation is not accurate.

The bodies of millipedes are typically cylindrical, and the average length varies between 1-5 inches.

Background coloration can be red, orange, brown, or even black, while the legs are consistently a reddish coloration.

The head is round, and consists of a pair of eyes, a pair of short antennae, and chewing mouthparts, or mandibles.

The mouthparts are utilized to feed upon various decomposing plant materials, although very rarely they have been known to feed on putrefying flesh.

Texas striped millipedes prefer to live in semi-arid to arid habitats of western Texas, including grasslands, creosote flats, sandy deserts, and sparsely-vegetated mesas and mountains.

They avoid desiccation by spending the majority of the day hidden underneath rocks, fallen logs, or man-made debris piles.

During dry weather, they will surface to forage only at night. But during times of rainy conditions, many will be seen crossing urban roads immediately after a substantial rain event.

The millipede’s locomotion is slow and steady, and this pace makes them vulnerable to predation from birds and mammals. To protect themselves, they will often roll themselves up into a coil, only giving the potential predator access to their hard exoskeleton.

If that fails to deter whatever they perceive as a threat, they subsequently emit a gas, which contains tiny doses of cyanide. This gas is quite malodourous, and will often trigger a gagging reflex in the predator.

Despite the noxious gas, the Texas striped millipede is harmless to humans (unless one were to place several of them in their mouth – not a good idea!), but they are often confused with the dangerous Giant Centipede.

One way to distinguish the two is to examine the number of legs present; millipedes have 4 legs per body segment while centipedes have only 2.

Millipedes also have a much more relaxed pace, moving slowly in a straight line forward. On the other hand, centipedes have a tendency to be much more erratic, moving forward, backward, and side-to-side at a much faster pace. 

Michael Price is owner of Wild About Texas, an educational company that specializes in venomous animal safety training, environmental consultations and ecotourism. Contact him at wildabouttexas@gmail.com.