Strange AnimalsThe Manx is one of the oldest and most immediately recognisable cat breeds in the world, defined by its extraordinary absence: the Manx either has no tail at all, a stub of a tail, a short tail, or very occasionally a near-normal tail, all varieties occurring within the same breed, with the tail reduction caused by a dominant genetic mutation.
The breed originated on the Isle of Man, a self-governing British Crown dependency in the Irish Sea, where geographic isolation allowed a spontaneous mutation to become common in the island's cat population.
The Manx is also the most genetically complicated of the "bobtailed" cat breeds, because the gene responsible for its taillessness can cause significant health problems when inherited in double dose, a characteristic that fundamentally shapes how the breed must be managed.
Origins: The Isle of Man
The Isle of Man is a small island, roughly 572 square kilometres, located in the Irish Sea between Great Britain and Ireland. It is large enough to have supported a cat population but small enough that a novel mutation could spread through that population over several generations.
The tailless mutation almost certainly arose as a spontaneous event on the island. Because the island was geographically isolated and cats could not easily arrive from or leave to the mainland cat population, the mutation spread. By the time formal documentation of Manx cats began in the 19th century, tailless cats were common on the island and regarded as a distinctive local type.
The breed received recognition in the early cat fancy. Manx cats have been exhibited in cat shows since the late 1800s. The Manx was one of the first breeds recognised by the Cat Fanciers' Association. TICA also recognises both shorthair and longhair (Cymric) varieties.
Several folk legends attempt to explain the tailless Manx. One story claims that Noah shut the door of the ark on the cat's tail just as it boarded. Another claims a tailless cat swam ashore from a Spanish Armada shipwreck. These stories are entertaining but implausible, and the Manx mutation is dominant and unrelated to the recessive gene behind the Japanese Bobtail's short tail.
The Manx Gene: Dominant and Lethal in Homozygous Form
The genetics of Manx taillessness are crucial to understand, and they distinguish this breed from all other bobtailed breeds in a clinically significant way.
Taillessness in the Manx is caused by a single dominant gene designated M (for Manx). "Dominant" means that only one copy of the gene is required to produce the tailless or shortened-tail phenotype.
The critical complication: cats with two copies of the Manx gene (MM homozygous) usually die in utero. The Manx gene affects spinal development, and having two copies causes such severe developmental disruption that the embryo cannot survive. This means that:
- All tailless or short-tailed Manx cats are heterozygous , they carry one copy of the M gene and one copy of the normal tail gene (Mm)
- Breeding two Manx cats together always produces some MM embryos that die before birth
- A typical Manx x Manx litter will be on average 25% MM (lethal), 50% Mm (Manx), and 25% mm (normal-tailed)
- The effective litter size is typically smaller than non-Manx breeds for this reason
This is why reputable Manx breeders often breed Manx cats with non-Manx cats (producing 50% Manx and 50% normal-tailed kittens) rather than Manx to Manx, to avoid the high rate of fetal loss and reduce the risk of Manx syndrome (described below).
Tail Length Varieties
The Manx's variable tail length is a consequence of the gene's variable expression. The main tail types are:
Rumpy: Completely tailless. A small dimple or hollow at the base of the spine where a tail would be. This is the "classic" Manx type and is eligible for show competition.
Rumpy-riser: A small number of fused vertebrae forming a short knob at the tail base. Visible but not extending beyond the rump.
Stumpy: A partial tail of fused vertebrae, up to about 3 centimetres long.
Longy: A tail of half to normal length. These cats are of Manx ancestry but do not carry the dominant gene, so they cannot pass it on. Longies do not qualify for most Manx show classes.
The longhair variety of the Manx is known as the Cymric , named after Wales (Cymru), though the breed was developed in Canada. The Cymric has the same genetics as the shorthair Manx but carries the recessive long-hair gene as well.
Manx Syndrome
Manx syndrome represents the most serious health issue specific to this breed, and all prospective Manx owners need to understand it.
When the Manx gene's developmental effects extend beyond the tail to affect the sacral (lower) spine and pelvis, the result can be a condition resembling sacral spina bifida, incomplete closure or formation of the sacral vertebrae. The consequences range from mild (subtle abnormalities visible only on X-ray) to severe (paralysis, urinary and faecal incontinence and inability to walk normally).
Severely affected kittens typically become apparent within the first few months of life. Signs include:
- Bunny-hopping gait (both hind legs moving together)
- Urinary or faecal incontinence
- Weakness or paralysis of the hind limbs
- Skin sensitivity or lack of sensation in the hindquarters
Kittens with severe Manx syndrome are typically euthanised. Kittens with mild forms may live normal lives or may have manageable problems.
The risk of Manx syndrome is higher in:
- Rumpy (completely tailless) cats, because complete taillessness tends to correlate with more severe spinal developmental effects
- Offspring of Manx x Manx matings, compared to Manx x non-Manx matings
Reputable breeders keep records of syndrome occurrence, and do not breed from lines with high incidence. Prospective buyers should ask about Manx syndrome rates in a breeder's lines.
Physical Characteristics
The Manx is a medium-sized cat with a broad chest and a firmly muscular body. The overall impression is one of roundness: a round head, round eyes and a round rump.
| Feature | Detail |
|---|---|
| Body type | Medium-sized, broad-chested, firmly muscular |
| Male weight | 4.5-5.5 kg |
| Female weight | 3.5-4.5 kg |
| Coat (shorthair) | Double coat; dense, soft undercoat with a longer, coarse outer coat |
| Coat (longhair/Cymric) | Semi-long, silky outer coat with thick undercoat |
| Colours | Virtually all colours and patterns (registries differ on pointed) |
| Eye colour | Often gold; follows coat colour standards |
| Hind leg length | Longer than forelegs, gives distinctive hopping gait |
| Lifespan | Reduced in cats with severe Manx syndrome |
The hind legs of the Manx are noticeably longer than the forelegs, giving the rump a raised appearance and producing a characteristic rolling or hopping walk. This is normal for the breed and not a sign of spinal problems in healthy Manx cats.
Temperament
Fanciers often describe the Manx as doglike in behaviour, as well as sociable and good-tempered.
Manx cats are also prized as hunters and were long in demand as farm cats and ship's cats.
Grooming
The Manx's double coat requires weekly brushing to remove dead hair and prevent matting, particularly around the rump and flanks. The Cymric's longer coat needs more frequent attention, especially during seasonal shedding. Neither variety requires professional grooming in most circumstances.
The Manx sheds moderately year-round with heavier shedding seasonally.
Cross-Links and Related Articles
- Japanese Bobtail
- British Shorthair
- Scottish Fold
- Senior Cat Nutrition Guide
- How Long Do Cats Live
Frequently asked questions
The Manx’s absent or shortened tail results from a naturally occurring dominant gene mutation (designated M) that arose on the Isle of Man. Only one copy of this gene is needed to produce taillessness. However, cats with two copies of the gene (MM, homozygous) usually die in utero, meaning tailless Manx cats carry exactly one copy of the gene (heterozygous).
Manx syndrome is a condition in which the Manx gene’s developmental effects extend beyond the tail to cause incomplete or abnormal formation of the sacral spine and pelvis. Effects range from mild spinal abnormalities to severe consequences including paralysis of the hind limbs, urinary and faecal incontinence and inability to walk normally. Severely affected kittens typically present within the first few months of life.
Reputable breeders keep records of syndrome occurrence and avoid breeding from lines with a high incidence.
The main types are Rumpy (completely tailless, eligible for show competition), Rumpy-riser (a bump of cartilage at the tail base), Stumpy (a partial tail of fused vertebrae up to about 3 cm) and Longy (a half- to normal-length tail). Longies are of Manx ancestry but do not carry the dominant gene. All types can occur in the same litter.
The Cymric (pronounced kim-rick) is the longhair variety of the Manx, sharing the same genetics but also carrying the recessive long-hair gene. TICA recognises the Cymric as a separate breed, the CFA classifies it as a longhair Manx. Both the shorthair Manx and the Cymric carry the same tail gene and the same risk of Manx syndrome.
The main health concern specific to the breed is Manx syndrome (sacral spinal defects), which is more common in completely tailless (rumpy) cats. Reputable breeders keep records of syndrome occurrence and avoid breeding from lines with a high incidence. A thorough health evaluation of any potential kitten by a veterinarian is advisable.
Fanciers often describe the Manx as doglike in behaviour, as well as sociable and good-tempered. Manx cats are also prized as hunters and were long in demand as farm cats and ship’s cats.
References
- Lyons LA, et al. "Feline genetics: clinical applications and genetic diversity of cats." Veterinary Clinics of North America: Small Animal Practice. 2012;42(5):1111-1127.
- Deforest ME, Basrur PK. "Malformations and the Manx syndrome in cats." The Canadian Veterinary Journal. 1979;20(11):304-314. PMID:498890
- Cat Fanciers' Association. "Manx Breed Standard." CFA Official Publication, 2023. cfainc.org
- International Cat Association (TICA). "Manx/Cymric Breed Standard." TICA Official Publication, 2023. tica.org