5 Kinds of Centipedes & Millipedes Found in Washington! (state)
Did you see a centipede in Washington?
Many people consider these strange creatures to be some sort of mutant worms, but luckily, they’re not. 🙂
In truth, millipedes and centipedes are much more closely related to marine animals like lobsters, crayfish, and shrimp. The biggest difference is that millipedes and centipedes are land dwellers.
Having them around your house is a huge benefit despite their creepy appearance. Centipedes eat silverfish, cockroaches, spiders, and other household insects; millipedes, on the other hand, ingest dead material they encounter, an important step in the food chain that helps keep us fed! They also carry no diseases affecting people, animals, or plants.
5 centipedes and millipedes found in Washington:
#1. Greenhouse Millipede
- Oxidus gracilis
Greenhouse Millipedes are found all over Washington. They originated in Japan and were carried to the Americas and Eurasia during trading expeditions. They’re around 23mm (1 in) long.
These millipedes are different looking than many of their cousins. They’re largely black or brown on top, with white legs. However, instead of having a round, tubular body of plates that integrate smoothly, they appear rather bumpy.
Greenhouse Millipedes also have an interesting trick. Recall that millipedes are related to lobsters, crayfish, and shrimp, yet there are no water-dwelling millipedes because they lack gills. However, this species can retain a bubble of air around their spiracles and spend an extraordinary amount of time underwater.
Unlike other species, the Greenhouse Millipede doesn’t have eyes, instead relying on its antenna to find food, locate mates, and perform other essential functions. They give off a particularly noxious odor when threatened. They’re poisonous to predators, so very few things consume them. Luckily, they’re not dangerous to humans, provided you don’t eat a handful of them!
#2. Yellow-Spotted Millipede
- Harpaphe haydeniana
Yellow-spotted Millipedes grow up to 5 cm (2 in) long. Adults can have up to 20 body segments! They usually start with six segments and add a new segment with each molt.
This social species meet up in the tens of thousands to mate all in one spot and then go their separate ways. Unlike other millipedes in Washington, Yellow-spotted Millipedes eat conifer leaves (pine needles) that many others avoid. They prefer moist coastal areas with redwood forests.
Two alternative names for this species tell us a lot about its defense mechanism. It’s often called the Almond-Scented Millipede and, more accurately, the Cyanide Millipede. This powerful poison coats the millipede’s skin, giving it a bitter-almond scent. Most predators steer clear!
Although the concentration of Cyanide is enough to kill a hungry pigeon, the dose is not particularly harmful to humans if you wash your hands after handling them.
#3. Brown Centipede
- Lithobius forficatus
Brown Centipedes are 18-30 mm (0.7-1.1 in) long and dark reddish-brown, like a chestnut. They have very long antennae and a matching tail to confuse you as to which end is the front! Of course, the head appears bigger than any single body segment, so you can always tell; the exaggerated size comes from the oversized fangs next to the head. Those fangs deliver a venom that is highly poisonous (if you’re an insect).
Slugs, worms, spiders, and flies make up the bulk of this species’ diet. Its leg count will top out at 15 pairs when fully grown.
Brown Centipedes like to hunt in Washington at night and hide during the day. If they’re not doing you the courtesy of keeping your home pest free, they may be out in your garden doing the job there instead. They frequent compost heaps where other prey may be found or seek food on tree bark that provides a home to insects. They don’t eat plants, but they do eat things that eat your plants, lending the nickname “Gardener’s Friend.”
#4. House Centipede
- Scutigera coleoptrata
This species is the most common centipede in homes in Washington!
They’re yellow-grey, with three stripes running down their backs. You might consider them racing stripes with how fast they can scoot along!
The legs are thick and powerful near the body but taper toward the ends, contributing greatly to their ability to zip after prey. Their antennae are extraordinarily long to help them sense their next meal. Incredibly, the two “decoy” antennae on their back end aren’t just there to fool predators; they’re actual antennae that function just like the front ones!
House Centipedes may look creepy, but they can be a useful houseguest. Their favorite foods include insects and spiders, but they’re fast enough to catch and eat houseflies and grasshoppers, too. In addition, they like damp environments, which is why basements and garages are so attractive to them.
Outside, you’ll find them in damp spaces that stay cool, such as woodpiles, rocky areas with good hiding places, prey-stalking lookout points, or piles of leaf litter. If you have a compost pile, they’ll be there!
#5. Soil Centipedes
- Order: Geophilomorpha
Their coloring can range from white to reddish brown, and they’re slender to aid their movement through the soil. These creatures are a bit flatter than most centipedes. Since they spend most of their time underground, Soil Centipedes have no eyes.
They move through the soil like an earthworm, pushing the front of their body forward and dragging the back towards it before repeating the process. Their goal is to find insect larvae and earthworms to eat, and they use fangs like all centipedes do to capture their prey.
They can range in size from incredibly tiny to monstrously large. The smallest individuals are 1.9 cm (0.75 in), and the largest is 19 cm (7.48 in). Luckily, since they live in soil, you’re unlikely to find this type of centipede inside your home.
Soil Centipedes provide a huge benefit that you might not have thought of – managing soil quality! These bugs digest and release nutrients otherwise trapped in waste for years. Their burrowing also aerates the soil, like earthworms, which allows water, nutrients, and minerals to reach plant roots more effectively. So even though they’re creepy, we should be grateful they exist!
Check out these other guides about animals found in Washington!
-
The 33 MOST Common Birds in Washington!
-
The 8 Most Common Snakes That Live in Washington! (ID Guide)
Which of these centipedes have you seen before in Washington?
Leave a comment below!
*To explore more of the centipedes and millipedes that have been found near you, check out iNaturalist!
