Most would say, well obviously the number of legs – which is partly true. Millipedes have two sets of legs per segment positioned directly under their body. Centipedes have one set of legs per segment positioned on the sides of their bodies. If looking from the side, centipedes have a flatter body while millipedes are more rounded.

Has a centipede really got 100 legs? The word centipede literally means ‘100-footed,’ but most centipedes do not have that many, as it depends upon the number of body segments that make up its body, and this number varies by species, with a fully equipped adult centipede having between 15 and 177 pairs of legs.

Can they bite is the next question. Yes, they do, though the severity of the bite is directly related to their size, the bigger the centipede, the more severe the bite. Centipedes use a pair of hollow legs, adapted with claws, to bite into the skin. These pincer-like maxillipeds, also known as toxicognaths or ‘poison claws,’ are found under the first body segment and can also cause small puncture wounds and blisters when the centipede crawls across the skin. When a centipede bites a victim (as opposed to stings) it injects venom from stored internal glands. Although centipede bites may be painful, they are rarely fatal.

The symptoms of centipede stings vary depending on the degree of allergic reaction and the size of the centipede. Typically, bite victims have severe pain, swelling and redness at the site of the bite, with symptoms usually lasting less than 48 hours. Symptoms for those more sensitive to the venom’s effects may also include headache, chest pain, heart tremors, nausea and vomiting.

Victims from centipede bites are often gardeners. The venom administered through a centipede bite is typically harmless, not life threatening to humans and symptoms are fleeting, lasting only a few hours. However, the larger the specimen, the greater the pain will be. Small children and individuals with known insect allergies may experience more severe reactions.

Always contact a physician for advice and treatment of centipede bites.

So, does a millipede have 1,000 legs then? No – on average they have close to 300 legs (which is still a heck of a lot!), with one particular species called Illacme plenipes having the most with around 600, which is twice the average of other millipede leg counts. They were first seen in 1926 but were not found again for 80 years when they were rediscovered by a student from East Carolina University.

Anyone who is a gardener will recall seeing millipedes in Portugal – black and shiny, often coiled into circles, at first glance you would think it was a worm. This particular creature is called a Ommatoiulus moreleti, or more commonly known as a Portuguese Millipede – yes, Portugal has its very own millipede! It is native to the Iberian Peninsula but has gained a ‘foothold’ in other countries too – in particular somehow accidentally, it has reached Australia where it has made a nuisance of itself and has become an invasive species.

There are well over 1,000 species of millipedes worldwide and for many of these, only a few experts can tell them apart. Millipedes normally live outdoors where they feed on leaf litter, damp and decaying wood, fungus and vegetable matter like tender roots, mosses or green leaves on the ground.

Portuguese millipedes will curl up into a tight spiral when disturbed, or try to escape with thrashing, snake-like movements. They are 20-45mm long with 50 body segments when fully developed. They have rows of glands that secrete a pungent yellowish secretion when the millipede is agitated. This secretion is composed of organic chemicals called quinones, which make the millipedes distasteful to predators such as birds. They congregate in large numbers and are quite mobile, especially after the first rains in autumn.

I had a fleeting random thought – imagine the complications of buying shoes for any of these critters. I have enough trouble getting one pair to fit comfortably!


Marilyn writes regularly for The Portugal News, and has lived in the Algarve for some years. A dog-lover, she has lived in Ireland, UK, Bermuda and the Isle of Man. 

Marilyn Sheridan