penny, cats will sometimes will swallow string, yarn, etc. It's more of an individual thing, I think. They're not as prone to it as some dogs. The first time I discovered this I had folded clothes, and set the girls bathing suits on the couch for the girls to put up later. One of the girls complained she couldn't find her bathing suit bottoms. A couple days later, I noticed it being colorful in the area of the yard, that the dogs used for their bathroom. Dang, they had shredded her bathing suit, and ate it, and pooped it out.
Next time I folded their clothes, and set them on the couch, I payed attention. One of the Chow Chows grabbed another bathing suit bottom, and began playing with it. Immediately, another joined in. They tugged, pulled, stretched, that poor bathing suit. They LOVED that stretchiness. When they finally pulled it apart, they sat down, and began tearing it to small pieces, and eating it. That nice stretchy material was too much for them to resist. From then on, bathing suits got put up immediately.