The reasons why cats always bite their nails are:

1. Cats love to be clean. If their nails are dirty, they will take the initiative to lick them.

2. When the area around a cat’s nails feels uncomfortable, injured or itchy, the cat will bite the nails and around the nails. It is possible to prick the cat's paw pads. At this time, the cat will take the initiative to bite its nails.

3. Cats, like humans, also have things they are not used to or don't like, and they will also be in a bad mood. When cats are in a bad mood, they bite their nails to relieve themselves.

The solution to cats always biting their nails is:

1. Find the main reason why the cat is in a bad mood, help the cat solve the problem, and it will gradually get better. . At this stage, you need to pay more attention to and accompany the cat more, and find ways to make the cat happy and return to its original life.

2. If the nails are dirty or too long and cause biting, the owner should pay attention to cleaning the cat's claws to prevent bacterial growth and trim the cat's nails regularly.

3. The cat suddenly chews its own feet. It may also be due to interdigital cysts or ringworm on the cat's feet, causing discomfort to the cat's paws. Therefore, the discomfort can be relieved by biting. At this time, the owner should carefully observe the cat's condition and treat it promptly if necessary.