All Siamese have a creamy base coat with coloured points on their muzzles, ears, paws and lower legs, tails and (in males) scrota. The pointed pattern is a form of partial albinism, resulting from a mutation in tyrosinase, an enzyme involved in melanin production. Siamese have almond-shaped, bright blue eyes and short, flat-lying coats. Many Siamese cats from Siam had a kink in their tails but over the years this trait has been considered to be a flaw and breeders have largely eradicated it, although it persists among street cats in Thailand. Many early Siamese were cross-eyed to compensate for the abnormal uncrossed wiring of the optic chiasm, which is produced by the same albino allele that produces coloured points. Like the kinked tails, the crossed eyes have been seen as a fault and through selective breeding, the trait is far less common today.
Wichien-maat" (Siamese) cats have existed for centuries in Thailand (formerly Siam). The pointed cat known in the West as "Siamese" is one of several breeds of cats from Siam described and illustrated in manuscripts called "Tamra Maew" (Cat Poems), estimated to have been written in the 1700s. The original Siamese imports were, like their descendents in Thailand today, medium-sized, rather long-bodied, muscular, graceful cats with moderately wedge-shaped heads and ears that were comparatively large but in proportion to the size of the head. The cats ranged from rather substantial to rather slender but were not extreme in either way. By the mid-1980s, cats of the original style had disappeared from cat shows, but a few breeders, particularly in the U.K., continued to breed and register them, resulting in today's two types of Siamese – the modern "show-style" Siamese, and the "traditional" Siamese, both descended from the same distant ancestors, but with few or no recent ancestors in common.
Siamese are affectionate and intelligent cats, renowned for their social nature. They enjoy being with people and are sometimes described as "extroverts." They are extremely vocal, with a loud, low-pitched voice that has been compared to the cries of a human baby, and persistent in demanding attention. They usually get on well with other cats, though they tend to be somewhat dominant, but they also have a great need for human companionship. Often they bond strongly to a single person. These cats are typically active and playful, even as adults.
