I have never seen a curly tail cat in the flesh! But they are not that rare it seems. There is one well known cat breed that is based on the fact that a part of their anatomy is curly, the American Curl (curly ears). And there are a bunch of cat breeds, LaPerm, Selkirk Rex, Tennessee Rex, Devon Rex, Cornish Rex and many more lesser known rex cats who have curly hair. We like curly!
Genetic mutations have caused the above breeds to come into existence. The same has happened to produce a purebred cat breed that is not yet that well known, namely the American Ringtail cat, the curly tail cat that has a pedigree.
But there are many other curly tailed cats out there that do not have a pedigree but have that tail. There are two important point about curly tailed cats:
- the genetic mutation that produces the curly tail is not harmful to the cat – sometimes genetic mutations can have unwanted detrimental effects as well as the characteristic for which the cat is bred.
- there are a wide variety of curly tails from tails that simply lie on the back of the cat to those that form a corkscrew.
OK enough – back to cats. The above pic, by the way is of a curly tailed lizard – photo by SteveMcN (new window). It was taken in the Bahamas. Nice pic (cropped as allowed under the license).
What of the genetics that are in play? Beth Gardner co-breeder of the American Ringtail, talks us through it. The first point to note is that this is still work in progress but a good hypothesis has been argued. The curled tail is due to the presence of polygenes (new window) (a “polygenetic trait”). At least two genes are present that create the curl.
One gene creates the aerial configuration. This is thought to be a dominant gene (new window) and sex linked meaning it is carried on the X chromosome.
The X chromosome is one of the two sex-determining chromosomes in many animal species, including mammals (the other is the Y chromosome)…..Females have two X chromosomes, while males have one X and one Y chromosome……(src: Wikipedia®)
Beth Gardner says that the factors that indicate a sex linked gene are:
- female cats with a ringtail fully expressed (occurring early on) are the offspring of parents who each carry the dominant gene and also carry the recessive gene).
- the curly tail is expressed in a similar way to that of the red colour in cats, which is caused by a sex linked gene.
- when a outcross parent is used in breeding, female offspring display tails that are partially aerial, which is believed to be due to only one copy of the dominant gene being present (two needed for full expression).
The other gene, the recessive (new window), is thought to produce the tail that curls and is independent of the dominant aerial gene. As mentioned, it is not extremely rare and can be seen, for example, Beth says, in feral cat colonies around Hayward in California, USA, (see map below) the home area of the purebred American Ringtail cat.
OK, lets see a curly tail cat! The pictures below are thumbnails. Click on them to see larger versions. There are published under creative commons licenses: (a)Attribution-Non-Commercial-No Derivative Works 2.0 Generic and (b) Attribution 2.0 Generic.