There are two reported instances of Manx cats’ tails being docked. There may be more. It should be said at the outset that the lack of a normal tail in Manx cats is due to a random gene mutation occurring on a island setting (Isle of Man) which confined the cats to a relatively small area which promoted longterm inbreeding. This developed the famous tailless cat which was picked up by cat breeders who ‘refined’ it over many years.
Therefore, on the face of it, there is (and was) no need to dock tails. However, as mentioned, there are two situations at least which has resulted in the tails of cats being docked.
I am told that some Manx cat suffer pain in their partial tails. Also some tails are kinked. In these cases the tails are sometimes docked by the breeder as a preventative measure. It occurs to me that some unethical breeders might be tempted to refine a stump of a tail with judicious docking. I have no evidence of it and if someone has please leave a comment. How do breeders create healthy Manx cats?
The second instance of tail docking concerns fraudulent behaviour. These are fake Manx cats. At one time Manx cats were regular looking cats with no tail. Unscrupulous dealers on the Isle of Man were known to amputate the tails of ordinary moggie kittens to instantly create an expensive Manx cat. They’d have no pedigree but if a tourist to the island wanted a souvenir they might be convinced to buy one at an exorbitant price.
There is a record from 1903 of visitors to the island being offered tailless cats on the pier at Douglas the capital. A commentator remarked that there were many more tailless cats than were born on the island sold to unsuspecting tourists.
There are four recognised types of Manx cat tail: the Rumpy, which is tailless, the Rumpy Riser, which is a tiny knob of a tail, the Stumpy which is short and movable stump of a tail and the Longy which is an almost full-length tail.
Modern Manx cats don’t look like the originals (see illustration above). They have been selectively bred to be very cobby i.e. have short, stocky bodies. And they lean forwards like hatchback cars. This is how cat associations visualised the appearance of this cat breed and the breeders follow their lead in breed standards. It would be all but impossible to dock the tail of a moggie and try and pass the cat off as a purebred Manx nowadays but I bet it still happens to gullible buyers.
P.S. In the UK it is a crime under the Animal Welfare Act 2006 to dock a dog’s tail other than for medical reasons in the dog’s interest:
A person commits an offence if (a)he removes the whole or any part of a dog’s tail, otherwise than for the purpose of its medical treatment; (b)he causes the whole or any part of a dog’s tail to be removed by another person, otherwise than for the purpose of its medical treatment.
The same must apply to cats even though they are not specified. Their protection must come under other more general provisions of the act.