The Maine Coon polydactyl
While Maine Coons are one of the most popular breeds, the polydactyl Maine Coon may not be well known to all cat lovers. They are, quite simply, pedigreed Maine Coons with extra toes on their paws. A regular cat has five digits on the front paws and four digits on the back but a polydactyl cat can have up to seven digits on each paw (with the maximum of eight being a rare exception).
The form of polydactyly that occurs in Maine Coons is known as pre-axial, that is, the extra digits are added on the inner or “thumb” side of the paw. In this form, the trait is harmless and was a common feature of the early foundation cats that would one day become the Maine Coon breed. Expression of this trait is random – the extra digits may be only one paw or up to all four (“4 wheel drive”) and the number of toes can vary from paw to paw. Most commonly, both front paws or all four have extra toes, but any arrangement may occur.
There are two types of paw formations; the mitten paw and the patty or snowshoe paw. The reason for these two types of expressions are likely due to two different specific mutations that causes the polydactyl phenotype expression. The mitten paw is self-describing, it looks like a mitten with a thumb (and usually at least one or more dew claws). This look is created by the extra digit(s). An example: four toes, a smaller dew claw, a thumb and another dew claw. This configuration is normally caused by the point mutation called “Hw”. It was named “Hw” because it is found in the Hemmingway cats of Florida, United States. It also appears in the Pixie Bob cat Breed and the pedigree Maine Coons.
The patty paw is a well-rounded row of toes next to each other forming a large paw usually having no distinct thumb. This variant was first examined in 2011 in France. The variant was never isolated or even localized, but appears to operate in the same manner as the Hw variant, except that the expression is the patty paw with most of the time six digits. In a few documented cases this variant has produced six-digit mitten kittens. This variant, although unidentified, has been dubbed the Canadian variant since it first appeared from a Maine Coon foundation cat in Manitoba, Canada in 1992.