In human, polydactyly is considered a common occurence.
Dr Alan Green (MD FAAP), author, pediatrician, lecturer and keynote speaker says:
'Polydactylism, or having one or more extra fingers or toes, is probably the most common abnormality of development found at birth. Polydactylism is reported in about 2 per 1000 children. However, many of the simpler cases are taken care of in the nursery by the obstetrician or pediatrician and don't show up in these statistics' (ref 1).
Anne Boleyn, Winston Churchill and King Charles VIII of France (ref World Knowledge Library) are some famous polydactyls.
"Polydactyly is an ancient trait and but for a quirk of evolution, all modern animals would have 7 or 8 digits instead of just 5. The oldest known four-legged animals, Ichthyostega and Acanthostega, had 7 or 8 digits per limb. The "extra" digits were next to the thumb. The extra digits disappeared 350 million years ago, leaving modern animals with just 5 per limb. 100 million years after evolution opted for five digits, throwbacks to ancestral polydactyly occurred, as a fossil of a seven-toed reptile demonstrates. The fossil, an aquatic marine reptile called Nanchangosaurus, was an mutant or evolutionary throwback which lived 100 million years after other seven-toed amphibians had died out.” (Ref 2).
There has been concern in the Cat Fancies that polydactyly may be associated with other abnormalities that we would not want to encourage in cat breeding. It is important that we separate true polydactyl from other syndromes that happen to include extra digits such as Ellis-van Creveld syndrome which is a disorder of the skeletal dysplasia type and includes cardiac malformation, dwarfism, cleft palate as well as extra digits. This is an autosomal recessive gene found on the chromosome 4 short arm and quite distinct to the simple dominant polydactyl gene found in the Maine Coon cat.
The polydactyl gene in the Maine Coon breed is the standard benign autosomal dominant gene for polydactyly, Pd. This gene has been identified following the sequencing of the cat genome.
Preaxial polydactyly is caused by ectopic expression of the signalling molecule Sonic Hedgehog (SHH) in the developing limb bud. Mutations in the long-distant, limb-specific cis-regulator for SHH, called the ZRS, are responsible for the ectopic expression which underlies the trait. Populations of domestic cats which manifest extra digits, (including Maine Coons and the celebrated polydactylous Hemingway’s cats), also contain mutations within the ZRS. The polydactylous cats add significantly to the number of mutations previously reported in mouse and human, and to date all are single nucleotide substitutions.
The variant of the Pd gene found in Maine Coons and other North American cats has been called Hw and is slightly different to the Pd genes found in cats from Great Britain (UK1 and UK2). (Ref 3)
The Pd gene is harmless even when homozygous and is not known to be associated with other anomalies. It has complete penetrance.
Sarah Hartwell describes it thus; The form of polydactyly most commonly seen in cats is a simple autosomal (i.e. not linked to gender) dominant trait which does not affect the cat adversely and is not associated with other abnormalities.(ref 2)
Polydactyl is easy to select for or against when breeding Maine Coons. You must have a polydactyl to breed a polydactyl. If you do not have a polydactyl you cannot have one born in a litter.
There are 2 forms of polydactyly; pre-axial and post-axial. Axial refers to the folding of the embryonic limb. The "thumb” side is before the axis (pre-axial) and the "little finger” side is post-axial. In humans it is usually post-axial i.e. an extra little finger, whereas in cats it is normally pre-axial with the extra toe on the thumb side of the foot. The Maine Coon Pd gene is the pre-axial form.
The Pd gene in Maine Coons has a variable expression and can give rise to a varying number of toes with a natural maximum number of 7 toes on each foot. There are different phenotypes associated with the gene. The most common are "mitten paws" and "hamburger paws" and both are pre-axial.
In one of the first scientific articles on polydactyly in cats (1949), Charles Danforth (Dept of Anatomy, Stanford University School of Medicine) says: "Although the domestic cat normally has eighteen digits, five on each front foot and four on each hind foot, the occurrence of individuals with more than that number is not uncommon.” (Ref 4)
Earlier studies on guinea pigs had found one form of polydactyly that is lethal when homozygous.
Dr Danforth raised polydactyl cats in his laboratory and reported on 234 normal and polydactyl kittens in 55 litters. His matings reflected a simple dominant trait and he concluded that there was no evidence that the homozygous form was naturally lethal;
the data ...(is) sufficient to show that the type of polydactyly studied behaves as a simple dominant with good penetrance, but variable expression and to indicate that there is no reason to suspect the gene of being lethal when homozygous. (Ref 4)
For some reason it seems that in Germany, officials are of the view that the Pd gene is cats is in fact lethal when homozygous and they reference the Danforth article for evidence of this conclusion. We can only surmise that an error in translation many years ago led them to this erroneous conclusion.
More recently, Dr Solveig Pflueger’s article in the Cat Fanciers Journal 1998 expanded our genetic knowledge of polydactyly. In this article she states; "it does not appear to affect the cat adversely and is not known to be associated with other anomalies”(Ref 5)
There has been much scare mongering about the ethics of breeding polydactyl cats caused by the emergence of the "Twisty Cats” in 1998.
Dr Pflueger (MD, PhD, FACMG) is considered one of the world’s leading geneticists. Her 1998 article discussed the usual polydactyl gene (Pd) and the Twisty Cat gene (Tw). After reading her article I had a personal conversation with Dr Pflueger and we discussed the Pd gene and the Twisty Cat gene. Dr Pflueger stated categorically that these 2 genes were quite different genes, that the Tw gene has never been seen in the Maine Coon Cat and never would be unless someone introduces an outcross cat that carries the gene. (Ref 6)
The Tw gene is also a dominant gene with variable expression that gives rise to triphalangeal pollex-radial hypoplasia. An unknown polydactyl cat may in fact have this gene as in its mildest expression it can appear to be normal except for extra digits. However if used for breeding this polydactyl of unknown origin will produce 50% of its offspring with the Tw gene. Some of those will have severe radial hypoplasia (RH). Dr Plueger told me that if a polydactyl cat has been bred from with no incidence of radial hypoplasia then that cat has the usual benign Pd gene and not the Tw gene. (Ref 6)
As the polydactyl gene in Maine Coons has been bred for many generations and can be traced back to foundation stock, it is evident that this gene is not in the Maine Coon. Care must however be taken when introducing new foundation (as is allowed in the breed in the USA) to check that any new polydactyl does not have the Tw gene.
Another problem falsely associated with polydactyly is the split foot.
Syndactyly (hypodactyly) or split-foot is the opposite of polydactyly. Instead of having additional toes, the cat's forefeet (rarely the hind feet) have two toes giving it the appearance of a crab or lobster claw. In humans, the condition is sometimes known as "lobster-hand". The other digits have either been suppressed altogether or each of the cat's toes is made up of two or more fused digits. A paper by A G Searle (in "Annals of Eugenics" Vol. 17, Part 4, pp. 279-283, 1953) discussed the lobster-claw condition in cats; Searle noted that the anomaly was usually inherited as a dominant, and had suggested that the right side was often more severely affected than the left.
Syndactyly is rarer than polydactyly and is caused by the SP gene.
It is accepted that a good percentage of the breed were polydactyls originally. The definitive book of the Maine Coon "That Yankee Cat” by Marilis Hornidge discusses the standard;
"The paws are large and round with their prominent tufts. The number of claws in those paws was perhaps the most controversial of all issues in the final stages of setting up a standard. The traditional MC was frequently a polydactyl or many-toed cat, a genetic mutation that occurs with great frequency in the upper north-eastern United States...Whatever the reason for its abundance in this geographic area, the "poly” or snowshoe-footed cat is part of the Maine Coon legend. Polydactylism was so dear to the hearts of the original group of enthusiasts who drew up the MCBFA standard, that rather than divide the ranks, a special classification with its own standard was set up for cats possessing the trait.”
Some authors estimate the percentage of polydactyls in the breed to be originally as high as 40%. In an interview in 1976 (not long after the Maine Coon was first accepted for showing) one of the foremost experts in the breed Beth Hicks stated:
"I don’t know if you are familiar with it but there was a study done by someone connected with a university in the 1950’s which showed that 40% of the Maines were polydactyls. Now, this was before they came back on the show circuit.”
Sadly, it appears that this trait is being bred out of the Maine Coon simply to fit in with the dictates of the show world.
Polydactylism was not seen in other breeds when the Maine Coon was first accepted as a breed and all other breed show standards listed 5 toes in front and 4 behind. When the Maine Coon Breeders and Fanciers Association (MCBFA) were putting together a show standard there was a lot of debate surrounding the issue of polydactylism. There was some resistance to the acceptance of the Maine Coon—"it's only a barn cat after all” - and many felt that insisting on allowing the standard to reflect the polydactyl variation could be the death knell for its acceptance into the show hall. It was always the intention of that early group of dedicated fanciers that once the ordinary Maine Coon was accepted, they would then put forward the polydactyl standard. Early correspondence and literature dating back to 1969, shows that polydactyl cats were always intended to be accepted for showing and they were never viewed as deformed or detrimental.
The official publication of the MCBFA the "Scratch Sheet” of 1970 clearly shows that there was (and still is) a Maine Coon Polydactyl Standard voted in by the membership as follows:
""Our MCBFA Polydactyl Standard has been voted in by our membership, and the wording is as follows. The Maine Coon Polydactyl Cat should conform to the Standard of the Maine Coon Cat, with the exception that multiple toes are allowed on either fore or hind paws or both.”(Ref 7)
The Maine Coon Polydactyl Standard remains in effect today - it has never been removed. The Cat FAQ on the MCFBA web site refers to the trait: "However, modern purebred Maine Coons are rarely polydactyls. This is because all cat associations automatically disqualify polydactyls from competition in the purebred classes. Because of this, most polydactyls were culled from the Maine Coon breed decades ago and only a few breeders continue to work with them.”(Ref 8)
This goes some way in establishing that the attempted eradication of the polydactyl was simply motivated by show issues and not for any health reason.
The statement above that "all cat associations automatically disqualify polydactyls from competition in the purebred classes" is no longer correct as the New Zealand Cat Fancy has accepted polydactylism in the Maine Coon by altering the standard to allow for extra toes.
Article 4b of the MCBFA constitution clearly states that an object of the society is "..protecting the Maine Coon Cat from obliteration of any of its naturally evolved features.” But unfortunately the fanciers now at the helm are many years distant from those original devotees and have moved away from the polydactyl trait and preserving the breed’s heritage.
Those original breeders who instigated the acceptance of the Maine Coon clearly intended the polydactyl standard to be implemented as soon as the breed cemented its championship status. In a letter of 29th September 1973, the then President of the MCBFA Mr Ljostad says "We have a six toed kitten in our house too. You are right that they are not accepted at cat shows yet. We knew that many Maine Coons were polydactyl and did not want this trait to get entirely lost from the breed…..”(Ref 9)
The word "yet” at the end of the second sentence clearly indicates that this trait was intended to be recognised in the future.
Sarah Hartwell observes;
Polydactyl cats are said to be virtually non-existent in Europe, because "unusual looking cats" were destroyed due to witchcraft superstitions, practically eliminating the trait (Kelly, Larson, 1993). I do not know whether Britain was included in the generic term "Europe" or whether it meant mainland (continental) Europe only. In Norway, polydactyl cats are known as "ship's cats" as the extra toes supposedly gave them better balance on ships in stormy weather; they are not uncommon and polydactyl kittens are sought after pets. Polydactyl random-bred cats have been reported in Sweden though other European cat lovers (locations not reported) had apparently never seen a polydactyl. They are common enough in Britain to be considered unremarkable.
Polydactyl cats were considered "lucky" by sailors. Sailors also believed polydactyl cats to be superior mousers and ratters. Employed as ships' ratters and lucky mascots, they would have reached America with early British settlers hence their greater frequency in Eastern states. A disproportionately high number of "lucky" polydactyl cats, compared to normal-toed cats, would have found their way there. This would lead to a greater proportion of polydactyls than usual for a random-breeding cat population. (Ref 2)
The incidence in the breed today is unknown but is very much reduced from the original estimated 40%. This is because most mainstream breeders, who enjoy showing, do not breed polydactyls as they cannot be shown.
In her 2004 article in the "Maine Attraction”, Lucinda King writes;
"Recent discussions show that many UK breeders oppose the polydactyl, yet research by the writer shows that many of these breeders have polydactyls in the first 5 generations of their pedigrees. Indeed some of the top show cats in the UK come from polydactyl lineage. One argument for this is that a poly to non-poly mating will derive a litter where 40 to 50% of the resultant litter will be polys, but all of the litter usually have increased boning. Hence perhaps thereby producing the size often required to do well in show in the non-poly.
A crude analysis of members web sites of the two GCCF affiliated Maine Coon Clubs in the UK show that of those with pedigrees or pedigree names on their web sites that can be traced, 63% of these breeder members have polydactyls within the first 5 generations of at least one of their Dams pedigrees. This figure is lower for Sires with 37% having polys within the first 5 generations of at least one of their Sires. However, it must be remembered that a Sire will produce many more progeny than that of a Dam.”(Ref 10)
The Pd gene is widespread in Maine Coon pedigrees. Many breeders are concerned that their pedigree Maine Coon may be "contaminated" by the introduction of the Pd gene. What most do not realise is that this gene has been a part of the breed since before it became a pedigree breed, it continues to be a part of the breed, and it is almost certain to be found in the lines of their cats somewhere. Polydactyl Maine Coons have been bred from all over the world since the beginning of the breed and continue to be used. Many breeders do not understand that allowing polys to be shown does nothing to change breeding practices.
To substantiate the hypothesis that most Maine Coons have a poly in their background, Soozn Grindell of Mainelymagic Maine Coons decided to research the early foundation cats of the Maine Coon breed and write articles on those that were polydactyls. She started with Gray Luv Perry. She did a quick internet search and spoke with a few of the old breeders. Here is the story of Gray Luv Perry:
One of the early polydactyl cats seen extensively in the background of many breeding programs (poly and non poly) throughout the world was Gray Luv Perry. Through her daughter Abishai of Sundar (also a polydactyl) she is found throughout the entire Maine Coon breed.
Gray Luv Perry was one of the most influential cats in the Maine Coon breed. She was a blue solid with white polydactyl according to Pawpeds. Her daughter, Abishai of Sundar born on the 19th of April, 1972 was sired by the solid black, Sam Spade Perry. Abishai was also a blue solid with white polydactyl. No photos seem to exist of Gray Luv, Sam Spade or Abishai.
Gray Love Perry and Sam Spade Perry were foundation cats brought into the breed in the late 1960's or early 1970's by Mrs Phyllis Voth of Wisconsin. Rumour has it that Mrs Voth obtained her foundation cats from the Humane Society Shelter in Madison, Wisconsin. Mrs Voth is the breeder of Abishai of Sundar and all of her offspring, under the Sundar prefix.
Phyllis Voth mentored Ginny Malloy (Charmalot cattery) who is well known throughout the world as one of the early influential breeders of Maine Coons. Ginny Malloy's first breeding cat was Abishai's grand-daughter; GRC Sundar Sarisvati of Charmalot.
In an article on the Pawpeds site, "Ginny says that her cattery is still today based on Heidi Ho Richard III of Charmalot, (who tragically died of FUS and uremic poisoning at the young age of four), together with Sarisvati and two other very important females, Charmalot Bluesette and Charmalot Lady Rebecca".
The very first Maine Coon to achieve the distinguished merit status was Abishai's daughter, CH Sundar Tiffany of Tufpaws. "Tiffany" was confirmed as a DM on January 13, 1983. She was also the dam of the two Tufpaws national winners. It was another four years before the next Maine Coon CH Heidi Ho's Coon Victoria was confirmed as a DM on January 14, 1987, and another nine years before the first male DM, GC Lovabacon's Tom Terrificat. "Terry" had his DM confirmed on September 7, 1991.
Abishai is in the pedigrees of many Maine Coon catteries. While researching, I could not find one cattery who did not have Gray Luv Perry and Abishai in their lines.
Each of the breeders of the TICA Breed Committe has these cats in their lines: Coonyham, Tanstaafl, Chemicoons, Smokeycoons, Broadsway, Juliehills, and Shononcats
Other breeders such as Calicoon, Codycats, Hibou, Nascats, Tati-Tan, Willowplace, Woodpile...the list seems endless, have them as a foundation in their lines.
1. Pawpeds database. http://pawpeds.com/MCO/mchs/articles/Charmalot_cs.html
2. CFA website - Breed information http://www.cfainc.org/breeds/profiles/articles/maine.html
1. Greene, Dr Alan. http://www.drgreene.com
2. Hartwell, Sarah. 2001-2004, http://www.messybeast.com/poly-cats.html
3. Lettice, Hill, Devenney & Hill. "Point mutations in a distant sonic-hedgehog cis-regulator generate a variable regulatory output responsible for pre-axial polydactyly" Human Molecular Genetics, 2008, V17
4. Danforth C H. "Heredity of Polydactyly in the Cat”, Journal of Heredity,
5. Pflueger, Solveig. "Polydactyly and Related Traits” Cat Fanciers’ Journal Fall 1998
6. Conversation between S Pflueger and S Grindell, 25 May 2005
7. Scratch Sheet approx Spring 1970. The official publication of the MCBFA. Click here for copy of the Scratch Sheet.
8. Interview transcript: http://www.pawpeds.com/MCO/mchs/articles/DonShaw3.html
9. Private letter Sept 29, 1973 to Mrs Gould from Rodney A Ljostad President, MCBFA. Click here for copy of the letter from MCBFA archives
10. King, Lucinda. "So What Happened to the Maine Coon Polydactyls?” Maine Attraction, 2004
Polytrak a great site with lots of information, articles and a database of cats
Pawpeds an article about polydactyly
Polydactyly is a trait not a fault.
poly on the front feet only is called 2 wheel drive (2wd), poly on all 4 feet 4 wheel drive (4wd).
You can have mitten paws and hamburger (or patty) paws.