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.