Most of us are very familiar with the unique and eye-grabbing orange, black, and white coloring of the famous calico cat. But, what causes this coloring pattern? Is it a result of breeding and, if so, are calicos considered a separate, identifiable breed?
Below, we’ll walk through the genetic causes of calico coloring and whether these cats belong to a specific breed!
Is a Calico Cat Its Own Breed?
So, the main question first: Are calico cats an actual breed? The answer is a resounding no! In actuality, the tricolor black, white, and orange pattern that calicos share is their only identifying feature.
This pattern genetically appears in several different breeds and can’t be used on its own to identify any individual cat. Two members of totally different cat breeds, with varying sizes, origins, and physical structures, can accurately be described as “calicos.”
In effect, this makes calico coloring functionally the same as any other standard coat color. You, for example, can’t use a cat’s white fur to determine its breed. It could just as likely be a Japanese bobtail or Manx cat!
Notable Calico Cat Breeds
Now, we know calicos can belong to several different breeds. But, which cat breeds are most likely to feature calico-colored individuals? Luckily, we actually have a pretty comprehensive list of cat breeds that the tricolor pattern tends to show up in most frequently:
- Norwegian forest cats
- Japanese bobtails
- Persian cats
- Exotic shorthairs
- Maine coon cats
- British shorthairs
The frequency of calico tricoloring varies between these different breeds. Interestingly, Japanese bobtails appear to be the statistically most likely breed to develop calico patterns. However, Japanese bobtails, contrary to popular belief, are not only calicos. Their coat colors frequently include solid color or two-color patterns.
And, in the case of Maine coon cats, calico coloring is actually just one of 64 possible fur color combinations. So, it’s quite a delightful surprise to encounter a member of this breed with the distinct calico pattern. It means that the pattern won out against 63 other contenders!
What Causes Calico Coloring?
Despite the simple presentation of their coloring, there’s actually a fairly complex genetic process behind the phenomenon of calico cats. Fur color in cats is determined by genetic data that’s carried with the X chromosome. Two variants of this data (alleles) create black or orange fur color.
The reason calico cats are pretty uncommon is because they need both alleles to create the pattern. If one of the variants is missing, you’d simply see a solid orange or solid black cat.
As you might expect, the chances of receiving both alleles are significantly slimmer than receiving just one. The majority of cats will simply get a black, orange, or other allele color. That’s why most cats have solid-colored fur!
Because of this process, calico genetics are quite similar to heterochromia in dogs and cats. Except, instead of being passed through the X chromosome, eye color is determined by variation in melanin production.
In cats, the genes that determine heterochromia also usually determine fur color, but there’s no relationship between calico coloring and melanin production. As a result, calicos can have any feline eye color, whether it’s blue, green, yellow, etc.
History of Calico Cats
If you suspect that calico cats have a colorful, long history as representatives of several affectionate pet cat breeds, you’re right on the money! While the exact origin of the calico color variant is unknown, the most common theory is that they originate from Egypt. They were then imported by Mediterranean traders into Western European countries, including France, Italy, and Spain. In the late 1700s, some calicos were transported to North America.
That said, serious research into calicos didn’t really begin until the middle of the 20th century. It was then that researchers began trying to figure out the genetic cause of calico cats, finally in the 1960s concluding that feline fur genes were passed down through the X chromosome.
This convoluted history actually means calicos have a lot in common with Egyptian Mau cats. Both are believed to have come from Egypt, and to have been transported into Europe much later. In the case of the Egyptian Mau, however, it wasn’t until the second half of the 1900s that the breed was introduced to the Western world!
Are All Calicos Female?
You may have heard that all calico cats are female. But, is it actually true? The answer is actually more complicated than you might think.
It’s true that the vast, vast majority of calicos are female. This is because the mutation requires two X chromosomes, which generally only occurs in female cats. On the other hand, male calicos certainly exist and have been confirmed by researchers. Typically, the reason a male cat can be born with the calico mutation is that they also have a rare chromosomal mutation that results in multiple X chromosomes and a Y chromosome.
On the other hand, this mutation is exceedingly unlikely: Only 1 out of every 3,000 calicos is a male! So, while saying “all calicos are female” isn’t strictly true, it tends to hold up as a practical guideline. Nonetheless, we can safely add it to the existing pile of cat myths, right next to the urban legend that cats have nine lives.
