We received a picture recently from a reader of what appears to be small brown worms (or perhaps larvae). It was accompanied by a very simple question: “Can you tell what these are?” Unfortunately, the picture isn’t particularly clear, and we know no other information about the worm – if it even is a worm – in question (like where the “worm” was found, if it had any distinguishing characteristics, and so on). For this reason, we can only offer a couple of guesses based on what we do know, which, alas, is not much.

First, the picture:

Although we can’t be certain, the creature pictured above appears to be quite small. There is not an object in the picture that serves as a scale, but we would guess that worm to the right is no more than a half an inch or so in length. What is perplexing is that the creature to the left is much smaller, but only with respect to its length, and its body seems to have many of the same characteristics as the larger worm. Is the creature to the left a complete organism, or is it merely a part of some larger worm (or whatever the case may be)? We simple don’t know.

Although we have been casually referring to the creature our reader found as a “worm,” there is a good chance that it isn’t a worm at all. Readers almost always write to us asking about worms, but in many cases – indeed, probably most cases – they are actually encountering caterpillars (i.e., the larvae of moths or butterflies) of one sort or another. Moreover, it is very common to find caterpillars in or around your home (although we don’t know where the pictured creature was found, alas), so we think there is a decent chance the photo above is of some sort of caterpillar (or other type of larvae; caterpillars are the larval form of moths or butterflies, but of course there are other types of larvae). Also, worms are often found outside, especially in the garden or yard, and they tend to be bigger than (our approximation) of the size of the creature our reader photographed.

What kind of larvae did the reader find? There are always two possibilities that immediately come to mind, both of which we have written about on multiple occasions. The first is the moth fly larvae, which tend to be brown with distinct dark lines that run horizontally across their bodies, a phenotype that lines up well with the creature pictured above. Furthermore, it is very common to find moth fly larvae – we get reader questions about them all the time – so that lends more plausibility to the moth-fly-larvae hypothesis. Moth fly larvae, as well as their adult form (regular moth flies, of course), are often found in damp places, like near drains or pipes. If our reader found the creatures in such an area, we’d say there is a fairly good chance he found moth fly larvae.

The creature above might also be of carpet beetle larvae. Carpet beetle larvae are also a brownish color, and they have stripes on their body that are a pale color. Again, this description fairly well matches the pictured creature above. (How can it be that larvae with dark stripes and pale stripes both match the pictured creature? Simply because we don’t know what part of the body coloring is technically the stripes. Is it the dark bands or the pale stripes between them?) Carpet beetle larvae are also quite common, and they can be found all over the house. They often infest clothes in your closet or food in your pantry. So, if the reader found his creatures in one of these areas, perhaps he is dealing with carpet beetle larvae.

We don’t know what the small brown worms are in the picture above, but there is a good chance they aren’t worms at all. Instead, they may be moth fly larvae or carpet larvae, but that is all we can say.