Polydactyl Maine Coons: the extra-toed gene explained
What a polydactyl Maine Coon actually is, how the extra-toe trait is inherited, and why CFA disqualifies it on the show table while TICA accepts it.
The Register's newsroom · · 4 min of reading
A polydactyl Maine Coon is a cat born with more toes than the usual five in front and four behind, usually one or two extra per paw, caused by a single dominant gene rather than an injury or a deformity. The trait is harmless, well documented in the breed's own folklore, and treated very differently from one show association to the next.
What the gene actually does
The common form of feline polydactyly is caused by a point mutation known as Hw (for Hemingway) in the ZRS, a regulatory sequence that controls the sonic hedgehog (SHH) gene during limb development, and it is inherited as an autosomal dominant trait. One copy from one parent is enough to produce extra toes, which is why the trait can appear suddenly in a litter where only one parent carries it and why it normally passes visibly from an affected parent instead of hiding for generations the way a recessive condition can. The extra digits usually show up on the front paws, sometimes on the hind paws too, giving the paw a broader, mitten-like look that breeders have nicknamed accordingly. In the ordinary Hw form it is an anatomical variant rather than a disease: an extra digit on an otherwise normal paw.
Why the Maine Coon in particular
No one claims the Maine Coon invented the trait, cats everywhere carry it, but the breed's documented history gives it a plausible foothold. A breed that worked on cold farms and ships, the kind of population where a slightly broader paw was never selected against, was always more likely to keep a neutral mutation than a breed shaped by a single fancier's closed lines. Sailors on both sides of the Atlantic are often credited with favouring extra-toed ship's cats on the belief that a wider paw gripped a rolling deck better, a story that cannot be verified from any ship's log but is at least mechanically plausible, unlike the breed's other unverifiable legend about raccoon ancestry. What the written record actually shows is simpler: extra toes turn up often enough in old New England barn cat populations, the same population the modern Maine Coon was built from, that the trait and the breed have long been associated in the public imagination.
What a buyer actually sees
A kitten with six toes on each front paw looks subtly different from the standard, broader where a typical paw is narrow, and the extra digit usually carries its own small claw that needs the same attention as any other. Veterinary genetics laboratories offer DNA testing for the Hw variant, mostly useful to breeders who want to predict a litter's toe count rather than to a pet owner, since the trait is visible at birth and never needs a laboratory to confirm. Nothing about daily care changes: the same nail-trimming routine covers the extra toe, and the same litter box habits apply. The only practical note worth keeping is to check the extra claw during a normal trim, since a digit set slightly differently can be easier to miss.
Why the standard refuses it anyway
This is the part buyers misread most often. CFA's Maine Coon standard asks for five toes in front and four behind and lists an incorrect number of toes among its disqualifications, and most registries take a similar line. TICA is the notable exception: it permits polydactyly in a few breeds, the Maine Coon among them. That rule is not a judgment on the cat's health or temperament, both are unaffected, it is a rule about conformity to a written physical standard, the same logic by which CFA also disqualifies a kinked tail or crossed eyes. A polydactyl Maine Coon makes exactly as good a companion as any other, and reputable breeders who produce one from an otherwise correct litter usually place it as a pet rather than discard the line over it. Where it is disqualified, the rule is about the show ring's bookkeeping, not about the cat.
Reading the trait correctly
The practical summary a buyer needs fits in one sentence: polydactyly is a dominant, harmless, cosmetic trait that bars a Maine Coon from the CFA show ring, is accepted by TICA, and changes nothing else about the cat it describes. A breeder who mentions it candidly, rather than treating it as a flaw to hide, is usually a breeder being equally candid about everything else in the litter.
