Blue Maine Coon: Why the “Grey” Cat Is Officially Called Blue

Nobody actually calls this cat grey until they find out that’s technically more accurate. Registries insist on “blue,” breeders insist on “blue,” the pedigree paperwork says “blue” — and yet the coat in front of you is unmistakably a soft, smoky slate grey. There’s a real reason for the mismatch, and it says a lot about how cat-color naming works in general.

Cat fancy has used “blue” as the formal name for diluted black since the earliest breed standards were written, and it stuck for the same reason “cream” stuck instead of “pale orange” — it reads better on paperwork and sounds sharper from a show-ring announcer. The coat itself is unambiguously grey, sometimes with a faint blue-steel sheen in certain light, which is exactly why so many owners and shelters list the same cat as “grey Maine Coon” instead. Both terms point at the same cat; “blue” is just the term you’ll find on pedigree paperwork and in breed standards.

Blue is what happens when black pigment (eumelanin) runs through a dilute gene. The dilute gene spreads pigment granules more thinly and unevenly along the hair shaft, which the eye reads as a lighter, softer, cooler version of the original color. Black diluted becomes blue; red diluted becomes cream. Both parents need to carry a copy of the recessive dilute gene for a kitten to actually show blue, which is why it takes more deliberate pairing to produce than standard black or brown tabby.

Solid blue is the one most people picture and the one most commonly meant by “grey Maine Coon.” See how blue fits alongside the breed’s other 80-plus colors in our colors guide.

Green, gold, and copper are the standard eye colors paired with blue coats, and the cool grey fur tends to make green eyes pop especially. Shade of grey varies by individual, from a pale dove-grey to a much deeper charcoal-blue, and coat depth can shift slightly with age and season the way most solid colors do.

Uncommon, not extreme. Blue is a fully recognized standard color, so established breeders can produce it reliably when both parents carry the dilute gene — but because that gene is recessive, it’s far less frequent in general breeding stock than black or brown tabby. Waiting lists for solid blue kittens run longer than for the breed’s most common colors, which pushes both price and patience upward.

Registered, health-tested blue Maine Coon kittens typically run $2,000–$6,000, sitting above the breed’s most common colors and below the very rarest shaded or chinchilla varieties. As with any color, the price should reflect health screening, pedigree, and rearing — not the coat alone. Our price guide covers what actually justifies the number and how to spot inflated “rare color” markups.

Coat dilution changes fur, not temperament. Blue Maine Coons carry the same gentle, sociable, dog-like personality as the rest of the breed — often described as calm and easygoing enough to suit families, seniors, and multi-pet households alike. Grooming, diet, and health screening follow the standard breed routine covered in our grooming guide and health problems guide.