What is the difference between a torbie and a tortie cat?

Also known as a patched tabby, torbie is a coat pattern made up of patches of red and brown tabby markings. The name is a combination of the terms tortoiseshell and tabby. A tortie (short for tortoiseshell) is made up of random patches of red and black, or blue and cream if the cat carries the dilute gene.

What breed are torbie and tortie cats?

Torbie and tortie (tortoiseshell) are coat colours and patterns, and not a breed. Both torbie and tortie occur in random-bred and some purebred breeds, depending on the breed standard.

Are torbie and tortie cats rare?

Tortie is a common coat colour/pattern combination and is widespread among purebred and random-bred cats. Torbie is the least common tabby pattern and is relatively uncommon.

For a cat to be torbie, she must inherit one copy of the red gene and one copy of non-red (usually brown tabby). The female carries two X chromosomes, one which carries the brown tabby gene and the other carries the orange tabby gene. To prevent a doubling up of genes in the female, one X chromosome in every cell is silenced, in a process known as X chromosome inactivation (XCI). As a result, some areas will display the brown tabby pattern while others display the red tabby pattern.

This process is exactly the same with tortie, calico and caliby cats (a caliby is a torbie with the addition of white).

As the male cat (XY) only carries one copy of the X chromosome, he will either be red or non-red.