We recently received a photograph of a green specimen from a reader. He provided a laugh-worthy description: “this little fellow came in as a stow away on one of my patients. Clung on really tight and was dancing like a kid at a pizza party! What is it?” We think the image of this worm dancing is hilarious, and to top it off we know what kind of worm this is!

Although we just used the word “worm” to describe the creature, it is in fact a caterpillar! This caterpillar is the larva of a geometer moth, and its commonly known as an inchworm. There are about 35,000 species of inchworms! In North America alone, there are more than 14,000 different species. Inchworms tend to be grey, green, or brown, and they use their earth-tone coloring to look like twigs or to camouflage into their surroundings. An inchworms has a set of legs on both anterior and posterior end, but none lining the middle of its body. The caterpillar moves by clasping its front legs and moving its rear end up, then clasping its hind legs and reaching forward to find a new attachment. This locomotion pattern is how these creatures were named “inchworms”; they look as if they are measuring their journey inch by inch! Inchworms mainly eat fruit and leaves, but some species also eat pollen, lichen, flowers, and other insects.

This inchworm might have ended up on a human when the human brushed against a tree or shrub. It is probably anxious to get back to the outdoors. We recommend our reader bring the caterpillar back outside where it can eat and move about in peace.

To wrap one, one of our readers found this green worm on one of his patients. We are confident that this green creature is an inchworm!