Although cats have often been depicted playing with knitting wool or string in works of art, in reality, yarn can be a deadly plaything.
Cats have rearward-facing barbs on their tongues that facilitate grooming and tearing meat from the bone. When a cat chews on wool or even string, it’s hard for him to spit it out because it gets stuck on the barbs. In some cases, this forces the cat to keep swallowing, and swallowing pieces of wool or string can cause severe intestinal tract injuries or internal blockage.
For the same reason, owners shouldn’t leave sewing needles with thread attached lying around. Cats may chew on the thread and swallow needles by accident.
Christensen, Wendy, and the Staff of the Humane Society of the United States. (2002). The Humane Society of the United States Complete Guide to Cat Care. New York: St. Martin’s Press.
