The blotched (classic tabby) pattern is the most common for domestic and stray cats in the UK today. It is unclear why the classic tabby is more common than the striped (mackerel) tabby.
As the domestic cat’s wild ancestor has a faintish striped tabby coat you might have thought that the striped tabby would be more common than the swirls and bullseyes of the blotched variant. But apparently not.
It is believed that all domestic cats carried the genes for the striped tabby until about 2,000 years ago, or more recently. For thousands of years after the first domestication of the wildcat in around 7,500 BC (about 9,500 years ago) all domestic cats were striped tabbies. There were no choices. They were like the old Ford cars which always came in one colour (black).
The blotched tabby started with a genetic mutation. The gene that creates the blotched tabby is recessive. Therefore, there has to be two copies for a cat to have this coat. This means that they have to inherit one copy from their mother and the other from their father.
If one parent has a striped tabby coat and the other a blotched tabby coat their offspring will be a striped tabby. This would be a barrier to the spreading of the blotched tabby population. However, for an unknown reason the blotched tabby in Britain and in the United States outnumber stripped tabbies by about two to one.
This means that more than 80 percent of cats carry the blotched version of the gene.
Interestingly, in many parts of Asia this ubiquitous cat coat is rare and even absent. You’ll see them in Hong Kong because they were imported into that region when it was a British colony by the British who brought their cats over.
The scientists would say that for a recessive gene to spread throughout the cat population it would have to be advantageous in terms of survival. They were rare at one time with about 10 percent of the domestic cat population being blotched tabbies by around 1500 AD (CE).
I am told that most Brits prefer the striped tabby over the classic variant. So, popularity cannot account for its successful spread in the UK. Also, the classic tabby does not provide better camouflage than the striped so why is it more common? I have to end on a disappointing note and say that we don’t know.
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