Photographs of a worm was taken by this reader, who asks what it might be. The worm in question is black in color, with ridges that segment its body. It also appears to be have thin appendages that protrude from one end of its body.
Unfortunately, no context was provided in conjunction with the photographs, but from the photograph and what we can see on it, we would assume this worm to be an intermediate hooded owlet moth caterpillar (Cucullia intermedia). The caterpillars of the intermediate hooded owlet moths are considered arthropods, meaning they are worm-like creatures with a segmented exoskeleton that protects them from prey. Also known as the dusky hooded owlet moth, these moths are furry and gray when fully grown, with a wing-span of 48mm. The caterpillars of intermediate hooded owlet moths are a hairless, matte black color, and have segmented bodies, their legs thus divided accordingly. Most intermediate hooded owlet moth caterpillars will have orange markings on the sides of their bodies, and the caterpillar in our reader’s photographs does not. He even took a photo of the caterpillar on its side (see image below) and no such markings are visible.
Hence, we must entertain the idea that this creature is not an intermediate hooded owlet moth caterpillar. We do not have any other suggestions as to what this caterpillar may be, as in comparison with many other black larvae/caterpillars, it is the intermediate hooded owlet moth caterpillar that this one most resembles, however there is something our reader can himself do to find out if this identification is correct. What he can do is put the larva in a container with air holes and some food and wait to see what it might grow into. This way, he can observe what the creature will mature into and confirm or deny whether or not it is an intermediate hooded owlet moth. If he finds that it is not what we identified it as, he may feel free to send more pictures upon applying this method. Nonetheless, as we think it is, at the very least, some kind of caterpillar, the type of food our reader will want to put into the container would be some kind of leaf from a tree.
On that note, continuing with the assumption that it is an intermediate hooded owlet moth caterpillar, these critters eat mostly the leaves of various trees and shrubs, but also have been known to feed on the flowers of wild lettuce and daisies. They can be found primarily in the south of Canada to the northern and western parts of the United States. Their preferred habitats are deciduous and mixed woodlands, though just like many species of moths, they often end up in suburban areas for reasons of finding shelter. This is especially prevalent for the larvae, who are trying to find somewhere safe to pupate. We do not know where our reader found his larva, but if the case is that he found it in his home, then this is likely the reason the larva was present in that location.
To conclude, the worm our reader found is likely an intermediate hooded owlet moth caterpillar. Although we are not 100% certain about this identification, it is at least our opinion that our reader needs not fear for his health or safety. This arthropod poses no likely threat, but of course we advise caution when handling any creature.