As your cat’s nail grows beyond the blood supply, the surrounding layer starts cracking to make room for the new nail, and once the process is over, the layer is discarded.
While this is a normal part of their cleaning technique, chronic nail-biting in cats is not, and health issues can trigger it, most commonly by ringworm, a fungal infection.
A broken or injured limb can make it difficult for your cat to scratch their nails on their cat tree, as well as a medical condition that kept them in an inactive state.