A reader sent us a photo featuring several worm-like organisms sprawling on the branches of a bush or small tree. We count about a dozen of these fuzzy, black creatures. We can’t see other features, but our reader noted they have red heads. What could these be?

We are confident that these creatures are caterpillars. The black larvae will eventually pupate and mature into moths or butterflies. What species of caterpillars are they? Well, that is a question that is easier to ask than to answer! Despite knowing several details of the caterpillars’ appearance (black fuzzy bodies, red heads), it might still be impossible to make a firm identification. This is because there are over 20,000 species of caterpillars in the world, and many of which fit that description. However, we do have some ideas still.

The larvae could be Redhumped caterpillars. Although Redhumped larvae are typically more yellow than the specimens in the photo, they sometimes have thick black stripes, causing them to appear black. These caterpillars are distributed throughout the United States inhabiting a variety of fruit trees (including apple, cherry, pear, plum, and apricot), as well as an assortment of forest trees.

Another possibility is the Azalea caterpillar. These black larvae have mahogany heads and live in azalea shrubs throughout the Southeastern United States. They are gregarious feeders that are most prominent during August and September. While the physical description seems like a perfect match, the plant in the photo does not look like an azalea.

To wrap up, we don’t know if either of these are the species of caterpillars that our reader discovered. As we explained earlier, caterpillars can be really tricky to identify. Sometimes two caterpillars of the same species look very different, while two caterpillars of different species look almost identical. Knowing what type of plant the caterpillars in the photograph are lounging on would be a crucial clue in solving this mystery!