Yesterday we received one of the simplest questions we have ever been sent. The reader submitted a photo of a creature and asked only if it is a centipede or millipede. There were no complicating factors, so he was basically looking for a one-word answer. We think our reader found a millipede, and in what follows we explain why. In doing so, we will outline the difference between centipedes and millipedes, providing a concise guide that will help you determine whether you have found a millipede or centipede.
Both millipedes and centipedes are arthropods – that is, they both belong to the phylum Arthropoda – but each are part of their own class. Millipedes make up the Diplopoda class and centipedes makes up the Chilopoda class. As we will see, the creatures are distinct in a number of different ways, but they are commonly confused with one another because they are both cylindrically shaped creatures with tons of legs. They also might be grouped together in a loose way because they aren’t insects, arachnids, or worms – they’re the bugs that fall outside of these categories, and many of them happen to look quite similar. And this brings us to the creature our reader found:
ATTENTION: GET PARASITE HELP NOW! At All About Worms we get a lot of questions about skin parasites, blood parasites, and intestinal parasites in humans. Because we can't diagnose you, we have put together this list of doctors and labs who understand and specialize in dealing with parasites in humans! That resource is HERE
We are pretty confident this is a millipede, but what’s interesting about the above creature is that it actually straddles the morphological categories that divide centipedes and millipedes. More precisely, centipedes are known to have long legs that extend beyond their bodies, and their back legs trail behind their bodies. They also have long antennae that are easily visible. In contrast, millipedes’ legs tend to be tucked under their body, sometimes to the extent that they can’t even be seen if you are looking at the creature from above. The rear legs are also aligned with the rest of their legs, and their antennae can be short and difficult to spot. As you can see, the creature above seems to kind of blend the characteristics. However, these phenotypical descriptions aren’t extremely rigid, and there is a great deal of diversity among centipede and millipede species. Thus, it shouldn’t be surprising that some millipedes look a bit like centipedes, and vice versa.
The reason we think the above creature is a millipede is because, despite its liminal morphology, it appears to have two leg pairs per body segment, whereas centipedes have only one pair per body segment. The number of legs per body segment is a sure way to tell the two apart, and the creature above definitely appears to have two per segment. (For the record, millipedes have only one pair of legs per body segment on the first three segments, so you have to look beyond these when trying to decipher between the two.)
|No Paywall Here!
All About Worms is and always has been a free resource. We don't hide our articles behind a paywall, or make you give us your email address, or restrict the number of articles you can read in a month if you don't give us money. That said, it does cost us money to pay our research authors, and to run and maintain the site, so if something you read here was helpful or useful, won't you consider donating something to help keep All About Worms free?
Since we are looking at a picture, we can only use these physical characteristics to determine what our reader found, but for the sake of completeness we should note that behavioral traits also distinguish centipedes from millipedes. The former tend to be quite quick, able to dart around a room and take cover, whereas millipedes move at a decidedly slower pace. If you’ve ever seen one crossing a road, you’ll fear for its life because its progress, with its legs moving in a vaguely wavelike motion to propel it forward, is so slow. Also, centipedes are generally predators that bite – they feed on creatures like earthworms – whereas all millipedes are herbivores that don’t bite.
So, despite superficial similarities, there are quite a few differences between millipedes and centipedes. When you look closely, they have distinguishing characteristics, and their behaviors are also district from one another. With this information, we hope we have not only answered our reader’s question, but have enabled to him to distinguish millipedes from centipedes in the future.