A natural genetic mutation results in a tailless or stumpy-tailed Manx. Manx originated in the Isle of Man, where the genetic mutation for no tails became prominent among the breed. But not all Manx cats lack a tail; they may be born with a short, stubby tail, full-length tail, or no tail at all. Fishman says the lack of a tail in Manx cats is caused by an incomplete dominant gene.