Manx SPCA Chronicle: The Health Consequences of Not Having a Tail

Last week’s article on the Manx cat focused on the history of this iconic breed, and this week’s article examines the cat as it is today and, in particular, the implications for health associated with not having a tail.

At the risk of upsetting Manx cat fans, strictly speaking the Manx cat is not a true breed in the biological sense as its lack of a tail is caused by a genetic mutation.

Scientifically speaking, a true breed has certain biological traits that only produce offspring with those traits when bred with another true breed.

Female Manx cats can produce kittens that have no tail, a short tail or a long tail – even within the same litter.

The genetic mutation that causes the absence of a tail is actually a deformity affecting the entire spine, causing vertebrae to be missing or fused together.

A Manx cat’s vertebrae tend to be missing or very short at the front of the spine, while those at the back may be fused together, causing loss of flexibility.

Sometimes the combination of genes produces a severe genetic mutation in the spine that results in a form of spina bifida.

Spina bifida is not a specific disease and is a general term used to describe an incomplete spinal cord that does not fully cover and protect the nerves within it.

Nerve damage can affect the messages sent by the cat’s brain, and in Manx cats this is most noticeable with regard to leg movement.

Some Manx cats seem unable to move their hind legs independently, giving them a bouncing, rabbit-like gait.

Where the genetic mutation extends to the pelvis, the Manx cat may have difficulty controlling its bladder and bowls; and some combinations can actually kill the cat (thus the Manx cat gene is sometimes called the “killer gene”).

Kitten embryos carrying the lethal combination of genes are often reabsorbed during pregnancy or may result in the death of the kitten.

About a quarter of Manx kittens are affected in this way, resulting in Manx cat litters being about 25% smaller than litters of most other breeds.

Another common genetic mutation in the Manx breed is polydactyly, where the cat has more toes than the norm – meaning more than five on the front legs and four on the back legs.

Polydactyly is rarely a problem and may or may not be passed on to offspring.

Tabby is considered the true color of Manx cats and Manx tradition states that there are three varieties of tabby: “spotted” tabbies have coats with lots of black spots in the fur; ‘blotched’ tabbies have larger circles of black fur; and “mackerel” tabbies have fishbone-like stripes.

Manx tabby cats are also said to have a capital “M” marked with black fur between their eyes – the “M”, of course, stands for Manx!

And a Manx cat’s tail length also has designated categories: “rumpy” cats have no tail at all (a “rumpy dimple” has a small indentation where the tail would start, and has no coccyx); ‘rumpy riser’ cats have the hint of a tail with a few vertebrae under the fur above the cat’s bottom; “stocky” cats have a short tail that tends to have limited movement; and “long” cats appear to have relatively normal tail length, with full mobility.

We have a very nice rumpy Manx cat in our cattery at the moment.

He’s a feral cat called Sloc but, now that he’s neutered, he can’t be sent back to the place of his name because he doesn’t get along with the other savages in the colony there.

Sloc is therefore available through our House a Mouser program which places feral cats in rural areas, such as farms and stables, where they will have an element of human contact and supervision. In return, they will help control the rodent population in the most natural way possible, using their legendary hunting skills.

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