“What is this thin, small, brow/tan, almost greenish inch worm?” writes this reader about the worm-like organism pictured below. “Found it dangling off my cap on a some sort of thread I think, it moves pretty fast. From the US.” Thanks to our reader’s excellent photo and video, but mostly the fact that she names the organism herself, we can confirm that this is indeed an inchworm. Inchworms are any caterpillar of a group of moth species found in North America. They are all characterized by their number and placement of appendages: legs at the front and back, but not in the middle. Due to how the legs are positioned on the body, the inchworm moves as it does in the video: by reaching for something to grab onto with its prolegs, then arching its back while the hind legs catch up.

Most species of inchworms are able to spin their own silk. They use this to construct their cocoons which they eventually will pupate in (pupation being the process during which a larva transforms into its adult form: in this case, a caterpillar into a moth), as well as to get away from predators. When in their natural habitat (on a tree or bush), inchworms will, when threatened, quickly spin silk and leap off their branch. Of course, they will be “dangling” on that “thread” just like they did off of our reader’s cap, so as to save themselves. Once the danger has passed, they simply climb their silk back up to their original perch to continue doing whatever it is they were doing, which is probably munching on some leaves.

Inchworms are not harmful to humans or animals, so our reader needs not worry about herself. They also do not tend to infest homes, as they would much rather stay in their natural habitat where there is plenty of food to eat. Just like in our reader’s case, inchworms typically find themselves in homes only when they are accidentally brought inside by someone, or someone’s pet. So, we just recommend taking the inchworm outside and leaving it near a tree or bush, where they will more than happily continue on with their lives in peace.

To conclude, the small, greenish worm our reader found on her cap is indeed an inchworm, and we commend her for correctly identifying it! We hope this proves informative, and we wish our reader the very best!

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