A couple of days ago a reader found some small black and brown larvae on the blanket her cats sleeps on. The cats’ blanket (and therefore the larvae) is lying on a hardwood floor in an undisturbed corner that hasn’t been cleaned for a while. The larvae appear to be limited to this corner, and they aren’t found anywhere else the cats go in the house. The reader was wondering what the black and brown larvae are, and specifically indicated that they might be carpet beetle larvae.

Along with all this helpful information, the reader sent along the following picture:

While this is not the most cut-and-dried carpet beetle larvae identification we have ever offered, we are still quite confident our reader is, as she suspected, finding carpet beetle larvae, which are by far the most common creature we write about – probably by an order of magnitude at this point. More precisely, she appears to be finding black carpet beetle larvae (Attagenus megatoma). Like other species of carpet beetle larvae, they are attracted to keratin, a protein that the larvae eat that is found in (among other things) animal hair. An infrequently cleaned blanket on which cats sleep in an undisturbed part of the house is basically a carpet beetle larva’s dream habitat.

The picture above also looks like a black carpet beetle larvae, which have more elongated bodies than other types of carpet beetle larvae. The reader says that the creature she found is about a half of a centimeter long, and while black carpet beetle larvae can get bigger, a half centimeter is firmly within their normal size range. Despite their name, not all black carpet beetle larvae are black, but they frequently are, and the one above happens to be black anyway (with some brownish stripes, which isn’t uncommon).

So, for all the reasons we have just presented, it seems very likely our reader found carpet beetle larvae. Fortunately, they seem to be localized to one corner of the house, so getting rid of them shouldn’t be a major problem. The cat’s blanket should be washed, and the corner that it sits in should be cleaned with an eye toward getting rid of the accumulated cat hair. Barring a larger problem lurking beneath the surface, this should take care of the problem.

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