We spent some serious time investigating Jossan’s 2,9 kg of weight. She is muscular, lean and not skinny. The vet said Jossan has a good size and proportions (and that is a veterinary that also breeds Siamese and Orientals, so she is quite familiar with the race). Still, 2,9 kg does not sound like much!

A healthy grown up Siamese cat usually weighs: male 4-6,5 kg (9-14 pounds); female 2,7-4,8 kg (6-10 pounds). Also, this article I found was interesting (Siamese cats are just mentioned):
Some healthy adult female Siamese cats weigh as little as 5 lb (2,26 kg) though some male Siamese can reach 20 lb (9 kg). Some Siamese breeding lines give smaller, more “fragile-looking” cats than others and the old-style Siamese cats are more robust than the rather skinny modern version of this breed.
The source: “FELINE MEDICAL CURIOSITIES: DWARF CATS, GIANT CATS, FAT CATS” written by Sarah Hartwell.

I guess that Jossan’s lean look is more of “a skinny modern” one, although her mum is more robust. Jossan is her daddy’s little copy.
Here is an interesting read about the history of Siamese cats and the descriptions of two different types of Siamese – the more round version, similar to the original Thai one, that was imported from Siam (Thailand), and more elongated, modern version of the race. From the article:
It is important to raise that several breeders believed that there were two types (morphologies) of Siamese. Mrs. Veley would have written herself that its cat (Pho) had a rather thin line and that its second cat (Mia) was rather robust and round. Thereafter, Mrs. Carew Cox, a judge of cat-show and founder of the first Siamese club, would have also noted, to see two types of lines : one compact, with a short body, short legs and a round head, while the other with a body and a semi-long, nimble and sinuous head.
