The Siamese (Thai: วิเชียรมาศ, RTGS: Wichianmat) is one of the first distinctly recognized breeds of Oriental cat. The breed originated in Thailand (formerly known as Siam), where they are one of several native breeds and are called Wichian Mat (วิเชียรมาศ, a name meaning "moon diamond"). In the 20th century the Siamese cat became one of the most popular breeds in Europe and North America.
The Thai or traditional Siamese shares some features with the Modern Siamese (e.g., the color pattern and the short single coat, although not so short and "painted on" as the modern) but differs from it in head and body type. It has a "foreign" type (rather elongated, high on the legs, lithe but substantial, with medium boning) not an "oriental" type as in the modern Siamese and Oriental breeds and it has a modified wedge head, with rounded cheeks from which project a wedge-shaped muzzle (or "marten face" as it was called in 19th-century descriptions). The ears are moderately large and higher than those of the modern Siamese. The eyes are medium to slightly large, a full almond shape but not extremely "oriental".
The breed standard of the Modern Siamese indicates an elegant, slim, stylish, flexible, and well-muscled body. Its head is triangular, with fine muzzle.
The eyes are almond-shaped and light blue ( a feature found only in purebreds), with large wide-based ears positioned more towards the side of the head. This positioning should form a perfect triangle from the tip of the nose to each tip of the ear. It has a long elegant neck and body and a wispy slender tail. The fur is short, glossy, fine, soft, tight, and adheres to the body with no undercoat. The Siamese is characterized by its typical pointed color scheme.
Siamese are usually very affectionate and intelligent cats, renowned for their social nature. Many enjoy being with people and are sometimes described as "extroverts". Often they bond strongly to a single person. Some Siamese are extremely vocal, with a loud, low-pitched voice—known as "Meezer", from which they get one of their nicknames—that has been compared to the cries of a human baby, and persistent in demanding attention. These cats are typically active and playful, even as adults, and are often described as more dog-like in behavior than other cats.
They are sometimes less active at night than most cats, possibly because the lack of a tapetum lucidum gives them poor night sight relative to other cats.