A reader recently sent us this message, “I find these in the bathroom every year around this time. It’s very skinny but long. It has antennae and moves like a worm. It isn’t as fast as a centipede, and doesn’t have any visible legs like a centipede. Also, I spray these with hairspray and they refuse to die, they keep moving around forever.” Here is the accompanying photograph:
We can see that the specimen is long and thin, as our reader described. We aren’t sure of its exact size because although the specimen is crawling on a tile floor, we don’t know the size of the tile so we can’t use it as a proper scale. We also know it has antennae. Our reader believes this isn’t a centipede, and we think she is probably right. We think this is probably a millipede. Based on what we know and what we can see, we are confident that this is the identification, but because the picture isn’t very clear, we can’t confirm this with certainty.
Millipedes are arthropods, not worms, but they do move across the floor like a worm would. They have lots of legs, but since their legs are so small they aren’t necessarily as visible as a centipede’s legs would be. (Millipedes have two pairs of jointed legs per segments while centipedes only have one pair per segment.) Also, like the organisms our reader found, they have antennae. Millipedes have hard segmented bodies that are often dark brown or black colored. Centipedes also have segmented bodies, but they are usually flatter and millipedes are rounder.
Millipedes typically live on forest floors where they can eat their fill of leaf litter, decaying wood, and other debris. Inside a home, they seek out dark and damp corners, like a bathroom or a basement. While readers do find them inside homes, they aren’t household pests. In other words, they aren’t destructive creatures that cause real problems like carpet beetle larvae or pantry moths. We believe the issue here isn’t the millipedes themselves, but how they are sneaking into the house. There might be a improperly sealed vent, screen, window, or door somewhere in our reader’s home. To truly get rid of these creatures, and other unwanted visitors, she will need to investigate for the secret entryway and have it sealed. She can also install a dehumidifier in her bathroom which will make it less humid and therefore less hospitable for these arthropods. Finally, sweeping up leaf litter and other debris around the outside of her home will help keep millipedes farther from her house and decrease the likelihood of them sneaking in.
In conclusion, one of our readers discovered a mysterious specimen in her bathroom. Although we cannot be totally sure based on the photo, we are convinced that she is dealing with millipedes.