Quick, what was that? It scuttled by in a flash, but you caught a few defining characteristics. It had many legs and a long, segmented, wiggling body. You know you’ve seen one before. Was it a centipede or a millipede?
A few unique characteristics help define which of our many-legged friends is which.
What’s the difference?
Both centipedes and millipedes are made up of segments that link together to form one, long body. With this body form in common, it might be hard to tell the difference between the two at first glance. Here are a few tips to spot the differences:
- Millipedes have two sets of legs per segment positioned directly under their body. Centipedes have one set of legs per segment positioned on the side of their body.
- Centipedes mostly eat insects after killing them with their venom. Millipedes feast on decomposing plants.
- If looking from the side, centipedes have a flatter body while millipedes are more rounded.
- They respond to threats in different ways. A millipede will coil up and release a smelly secretion. Centipedes can bite (which is typically harmless to humans) and run away quickly.
It’s all in the “family”
These two also have enough in common to make them “cousins” in the animal kingdom.
- Scientists have grouped them together because of their similar segmented bodies.
- Both have poor or non-existent vision and rely on other senses, like the feel of vibrations.
- They prefer to live in dark environments, which is why you may have seen them in an unlit corner of your basement.
- The longest species of each measure about six inches in length.
Say no to “Nope!”
Of course, they may not be the most pleasant creatures to some folks. There is, however, plenty to observe and you’ll find they really are quite fascinating! At the Carnegie Museum of Natural History, Curatorial Assistant Catherine Giles and Collection Assistant Vanessa Verdecia study these animals and many more in the Section of Invertebrate Zoology. Scientists like them across the world could use your help!
There are not many known studies of centipedes or millipedes, even though they are incredibly common and span the globe. Catherine said she would urge people not to say “Nope!” when it comes to centipedes and millipedes. Instead, we should be curious. Studies need to be done in the field with live specimens (ecology) and in labs or offices classifying specimens (taxonomy).
There are more than 3,000 known and an estimated 8,000 species of centipedes. There are upwards of 7,000 known and 80,000 estimated species of millipedes. Millipedes can be found in moist forest areas, while centipedes prefer dry environments. Try and find examples of both species. Take a closer look. Do you notice the differences outlined here? What about the similarities? If you were to study these creatures, would you prefer to be on the scene or in the lab? There’s no wrong answer as long as you don’t say, “Nope!”
“Milli” is a latin prefix for 1,000 and “centi” is for 100. Don’t assume that’s exactly how many legs each has on its entire body, though!
Some species of millipedes can have as many as 750 legs. Centipedes can have more than 350 legs.
Learn more in Nature Lab!