Cats bite on boxes for several reasons, including: 1. Teething or Playfulness – Kittens, and even adult cats, love to chew on things as part of play or to relieve teething discomfort. 2. Texture and Sensory Stimulation – The rough, slightly soft texture of cardboard feels satisfying to chew. 3. Marking Territory – Cats have scent glands in their mouths, so biting is a way to claim the box as their own. 4. Hunting Instincts – Biting and shredding mimic their natural behavior of tearing into prey.