Genetic Mutation

• Bobtailing is a genetic mutation that occurs in some cats regardless of breed, location and parentage. Because it is a mutation, one or two kittens from a litter can have a bobtail while others from the same litter have normal tails. Bobtailing occurs randomly throughout the world feline population. Bobtail mutations sometimes occur with other skeletal and neural tube defects, such as spina bifida, though many mutant bobtailed kittens are free of health problems.
  
  

Breed Characteristics

• The bobtail is part of the breed characteristic or standard for some cats. Some bobtail breeds were bred for generations to achieve a consistent bobtail appearance, while others developed as a result of natural selection. Highlander cats, Karellian bobtails, American bobtails and Manx cats are all identifiable by their short, bobbed tails. The American bobtail and Karellian bobtail breeds developed with little to no interference from humans and breeders select individual cats that display a strong propensity to carry on the bobtailed genes.
  
  

Accidents and Surgery

• Accidental injury or intentional abuse can cause a bobtailed appearance in cats. Trauma to the bones, ligaments and sensitive tissue in a cat's tail can cause a kinked appearance or result in the loss of some or all of the cat's tail. Surgical alteration can also give cats a bobtail in a manner similar to docking a dog's tail. Surgical alteration is usually only performed when medically necessary - as is the case with tumors or infection.
  
  

Abuse

• Some bobbed tail kittens are the result of abuse. In a 2008 animal cruelty case, a Pennsylvania woman was charged for altering the appearance of a litter of kittens. In addition to piercing their ears and other body parts, the woman wrapped a tight elastic band around the kittens tails to encourage them to fall off in order to give them a bobbed tail appearance.