In a series of short, descriptive sentences, a reader recently wrote us asking if any worms eat leather. The reader was in a secondhand store and came across a leather dog leash that looked as though it had been eaten by small worms. There were tunnels in the leash, possibly caused by some worm or worm-like creature, which made it look a “bit like furniture that was attacked by woodworm.” Overall, the leash lacked the structure of leather, however this is to be conceived, which made the leash look like a “uniform grey mass.”

Unfortunately, we know of no specific species of worm that eats exclusively (or even largely) leather, which makes this question a bit tricky. Since we don’t know of any worms that thrive on leather in particular, the extra details about the leash’s appearance, as descriptive as they are, don’t help us much in identifying this worm. However, we do know that there are a number of worms that feed on bizarre materials.

We should begin by saying that it is certainly possible that worms are responsible for the disintegrating dog leash described by our reader. Worms are known to consume all sorts of crazy stuff, as anyone who composts using worms can attest to. When left in a compost bin, a large range of materials will eventually start to fall apart thanks the unyielding appetite of worms, and there is no reason to suppose that this doesn’t apply to leather (after all, leather was once part of an animal, and worms certainly feed on animals). However, commercial leather products are treated with certain chemicals that could harm worms, meaning that new leather would likely not be consumed by worms. Thus, it’s possible that worms would eat leather, but only if the leather is really old; the chemicals used to treat leather would be really faint in old leather, so they would likely not harm worms if they tried to eat it.

One type of worm that eats strange materials are bookworms, a blanket term that refers to the larvae of different types of beetles, such as the cigarette beetle, the drugstore beetle, and the Mexican book beetle. Bookworms are extremely small (about .1 to .2 inches long) and get their name because they eat books, particularly old books that are bound with paste and glue. (This is why modern books use alum, or the ammonium double sulfate of aluminum, in the paste of their bindings – it discourages the larvae.) Bookworms eat all the parts of older books, including the leather covers. In fact, the larvae of the cigarette beetle are known to eat leather in general (among many other things), not just leather attached to books.

In conclusion, we don’t know what type of worm is responsible for the dog leash our reader saw, but we do know, one, that there is nothing in principle that would prevent worms from eating leather and, two, there are in fact types of worms that eat leather, like the larvae of cigarette beetles, which isn’t really a worm at all, but the larval stage of a beetle, but we digress.

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