The bobtail is a genetic mutation that causes a cat's tail to be shorter than average. Sometimes these cats don't have many problems coinciding with the bobtail, other than occasional balance issues. But other times it can cause spine and hip issues. Bobtails can also cause bladder issues and difficulties with jumping, although there are many bobtail cats that live normal cat lives. This kit will be one of them, though they will have minor issues with balance as a kit