They are the same breed, but their coat length determines what we call them. This is due to the acceptance of Cymrics coming much later than the acceptance of Manx. In some feline organisations, however (such as the CFA), Cymrics are simply named Manx Longhair.
Tails?
It's a common misconception that all Manx are tailless; there are 4 different lengths of tail;
Rumpy – completely absent of a tail
Rumpy riser – a small rise of bone at the base of the spine
Stumpy – a very short tail of a few inches in length
Longie – a full tail, although this is often still shorter than in most breeds
Regardless of short coat or long coat, no tail or a full tail, these incredible little guys are all Manx - or Cymric!
The Manx is one of the oldest recognised breeds, being documented from the 1700's, being in attendance at the first ever cat show and featuring in the first books written on pedigree cats.
There is a lot of folklore surrounding how the Manx cat lost its tail; from having their tail chopped off when Noah closed the door of the arc, to Vikings chopping off their tails to decorate their helmets for luck - and even a once long held notion of them being part rabbit or hare! In all likelihood, as much as we would love one of the latter explanations to be true, the simple explanation of the trait is that it was a natural mutation that, being dominant, lead to it’s fairly quick spread on a small island.
Excerpts from the GCCF website regarding Manx/Cymric health
The Manx taillessness gene is dominant and highly penetrant; kittens from two Manx parents are generally born without any tail. Being homozygous for (having two copies of) the gene is usually lethal in utero, resulting in miscarriage. Thus, tailless cats can carry only one copy of the gene. Breeders have reported all tail lengths in the same litter, and there is no accurate means to predict the ratio of tailed to tailless kittens produced in each litter. Because of the danger of having two copies of the taillessness gene, breeders generally avoid breeding two entirely tailless Manx cats together. However, in contrast, as neither parent carries the tailless allele, a tailed Manx bred to tailed Manx results in all tailed kittens. Therefore, controlled combinations of tailed to tailess and tailess to tailess matings are generally used to maintain overall litter balance, phenotype and genetic diversity.
"Manx syndrome" or "Manxness" is a colloquial name given to the condition which results when the tailless gene shortens the spine too much, as discussed above. It can seriously damage the spinal cord and the nerves causing a form of spina bifida as well as problems with the bowels, bladder, and digestion. Some tailless cats such as the Manx cats may also develop megacolon which is a recurring condition causing constipation that can be life-threatening to the cat if not properly monitored. It is a condition in which, due to absence of a tail, the smooth muscle that normally contracts to push stools toward the rectum loses its ability to do so. Very small bladders are also indicative of the disease and it is often difficult to diagnose. Death can occur quite suddenly and some live for only 3–4 years; the oldest recorded was 5 years when affected with the disease. In one study it was shown to affect about 30% of Manx cats, but nearly all of those cases were rumpies, which exhibit the most extreme phenotype. The breed is also predisposed to rump fold intertrigo and corneal dystrophy. Some partial tails are prone to a form of arthritis that causes the cat severe pain, and in rare cases Manx-bred kittens are born with kinked short tails because of incomplete growth of the tail during development; kittens with stumpy to long tails have sometimes been docked at birth as a preventative measure.
However it must be stated that these problems are now rare and can be avoided by observance of good breeding practices i.e. minimising the number of generations of tailess to tailess matings (maximum of three and preferably two) and the use of fully tailed Manx cats in the breeding program, as discussed above. These are responsible for a decline in spinal problems among modern, professionally-bred Manx cats today. Most pedigreed cats are not placed until four months of age (to make sure that they are properly socialised) and this usually also gives adequate time for any such health problems to be identified. These cats survived over many centuries, independent of outside interference from man, building a viable, self-sustaining population of free-breeding animals. This confirmed the inherent vigour, soundness and independence of this tailless phenotype in feral animals. The Manx cat has not been artificially derived by man from a naturally occurring mutation which has then been selected to build a novel breed. The tailless phenotype (and all its permutations) is still the predominant feature of naturally born domestic cats on the Isle of Man.
