|Photo published under Wikipedia Commons license. By Alex Opryatin|
This is a very rare cat breed. I call it one of the unusual cat breeds because you don't usually see cats from this breed.
Personally, I don't think this version of the Siamese cat is the "real legendary Royal Siamese" as Alex states. I am pretty sure that in Siam (now Thailand) perhaps 1000 years ago or so there were Siamese cats with normal tails, Siamese cats with kinked tails and the occasional Siamese cat with a shortened tail (bobtail). This is how nature works.
When the Siamese found its way to the west (Europe and USA) in the late 1800s breeders did not like the Siamese kinked tail, which was almost the hallmark of a Siamese with the pointing, and selectively bred it out. You can still feel the kink sometimes.
It appears that the bobtail version was not imported. The interesting point (excuse the pun) about the pointing of the cat in the picture is that it is quite restricted. What I mean is that it really is at the extremities of the cat, whereas normally you see the darker fur over the full face of the cat. In this instance the pointing is restricted to the nose and surrounding area. The same level of "limited pointing" is present on the lower limbs. You do see this sometimes in Siamese cats. I feel that it is wrong and less good than what I would call proper pointing.
I am going to add an update this page at 6th June 2012 because Alex Opryatin showed me his website and asked me to write a bit more about the Mekong Bobtail.
I say that the bobbed tail version of the Siamese was not exported to the West. Alex makes the point that a lot of cats in Asia have, how do I say this, "interesting tails". They are kinked or missing or shortened. The great Darwin refers to this in this in The Variation of Animals and Plants under Domestication, 1883". So does Harrison Weir the founder of the cat fancy when he writes about Manx cats and because of what he says I raise the possibility that this cat breed was imported from Asia to the Isle of Man.
Because of the prevalence of short tailed cats in Asia it is no surprise that the Siamese cat or a pointed cat developed a short tail - a bobtail.
Alex says that a number of the imported cats from Siam were Siamese cats with bobtails and the breed developed from there.