A reader wrote to us a little while back about some small worms she is finding in her cat’s food. The reader emphasizes that the worms are not in the food prior to giving it to her cat, which is good, but after the food has been out for a day or so, she often finds worms in it. The reader also finds small dark worms under the mat on which the cat food is placed, which is why we are writing about “small dark worms in and around cat food.” This rather specific title may imply we have a definite answer in mind, but unfortunately we do not. We do, however, have a few possibilities to suggest.
Unfortunately, the reader’s question is short on crucial details, and no picture was submitted along with her query. A picture would be especially welcome in this case, as adjectives like “small” and “dark” are not terribly descriptive. There are tons of creatures that might be called small and dark. “Small” could mean anything from a few millimeters to a couple of inches, and “dark” could mean various shades of brown or perhaps simply black. Fortunately, however, the reader did describe the “worm” as having dark brown ridges on it, which leads us to our first thoughts.
You’ll notice we put the word “worm” in scare quotes, and this is because the reader seemingly did not find a worm at all. Instead, we suspect she found some type of larvae, which can be worm-like in appearance because of their cylindrical bodies. A number of different kinds of insect larvae are found in foods, pet or otherwise. Because of the crucial “dark brown ridges” fact (which we take to mean something like dark stripes between the creature’s body segments), we are led to consider two possibilities: flour beetle larvae and carpet beetle larvae.
Both of these creatures match the reader’s physical description well, and both are common pests that are found in various foods in peoples’ houses. Based strictly on the amount we write about them, carpet beetle larvae seem like the more common pest, leading us to favor this hypothesis. Carpet beetle larvae also have more pronounced “dark ridges” than flour beetle larvae (sometimes flour beetle larvae are quite light and look almost exactly like maggots), which again leads us to think that carpet beetle larvae is the more likely creature in the cat food. As far as we know, neither creature has a particular proclivity toward pet food (indeed, flour beetle larvae tend to eat grains, which isn’t surprisingly given their name), but either creature might seek out an unprotected food source like a bowl of cat food sitting around.
The only other possibility worth mentioning briefly is flea larvae, which we bring up only because the reader seemed to vaguely imply that the creatures she is finding might be coming from her cat. (They are not in the food when the reader gives it to her cat, but they are after, as if the cat might have introduced them.) Flea larvae, the larvae of fleas that often afflict pets, are very frequently found around pets (often in their bedding, but conceivably in other places where pets frequently are, like by their food dishes), and are sometimes a dark color. However, flea larvae do not have dark ridges on their bodies, so we think this possibility is unlikely (but nevertheless worth mentioning given how often these “dark worms,” as one might incorrectly describe them, are found around pets).
To conclude, we aren’t sure exactly what our reader found, but we are confident she didn’t find any type of worm. She seems to be dealing with some type of larvae – beetle, flea, or otherwise – and hopefully we’ve at least led her in the correct direction.