haded Silver and Chinchilla are also caused by the dominant Inhibitor gene in combination with the dominant Agouti gene. The underlying tabby pattern is demonstrated by chinchilla kittens which appear silver tabby until the hair grows long enough for the white undercolour to be properly developed. As the hairs become longer, the tabby pattern is diffused and only the very tips of the hair are coloured, producing a sparkling effect. Occasionally a Smoke (Non-agouti) can be so light in colour that on visual inspection it is Shaded cat (e.g. a very light Black Smoke resembling a Shaded Silver); however it is different genetically.
The first silver chinchillas were developed from unsound or spoiled silver tabbies mated to lightly tipped smokes. Unsound or spoiled silver tabbies were those where the silver undercoat was evident at the base of the black hairs which formed the markings. Because chinchillas resulted from crossings to smokes, it was thought that a single factor (what would now be called a gene) was responsible for chinchillas, shaded silvers and smokes. There are light, medium and dark smokes and light smokes were sometimes mistaken for shaded cats and bred with chinchillas.
Selective breeding has increased the amount of undercolour and reduced the extent of top-colour. The long fur emphasises the undercolour and prevents the hair tips from forming a recognisable tabby pattern. Some tabby effects may still be seen in body areas with shorter fur: the face and lower legs. The longer the fur, the better the pattern is dissipated, hence shaded shorthairs are at a disadvantage compared to the longhairs. Although some Shaded shorthaired cats have a tabby pattern at birth, this should be dissipated by hair length in adulthood. Sometimes the tabby pattern persists into later life and is considered a serious fault (or the cat is quietly reclassified as a tabby). There are likely to be various modifier genes which further disperse the tabby pattern and reduce the pigmentation of the hair shaft by creating wider bands.
The Shaded Silver and the Silver Chinchilla (usually known simply as Chinchilla with no colour qualifier) are the most familiar of these cats and the longest established. They are not the only colour variants though. The Blue Chinchilla is the dilute form of the Chinchilla and appears almost identical. Blue Chinchillas are most easily distinguished as kittens when the blue colour is less diffuse.
The Chocolate Chinchilla is also most easily identified in kittenhood. Adult Chocolate Chinchillas have dusky-brown or "off-black" tipping. Lilac Chinchillas, Cinnamon Chinchillas and Fawn Chinchillas are also possible.
The Red Shaded Silver and Red Chinchilla (and also Tortoiseshell Shaded and Tortoiseshell Chinchilla) are produced by a combination of the Inhibitor gene and the gene for red. The difference in appearance between the Red Shaded Silver and Red Chinchilla is due to modifiers acting on the extent of the undercolour and top-colour along the hair shaft. The Agouti gene affects non-red colours such as black, blue, chocolate etc so it does make a difference in whether the non-red areas of tortoiseshells turn out as shaded/tipped (Non-agouti) or as silver tabby, blue silver tabby etc (Agouti).
The Cream Shaded Silver and Cream Chinchilla are due to the presence of the dilution gene in addition to the red gene. In the tortoiseshells, this additionally turns a red/black tortoiseshell into a blue smoke tortie or a blue silver tabby tortie.
In 1969 or the early 1970s, Mrs Worthy of Hertfordshire bred some unusual Devon Rex twins whose white coats were “sprinkled exotically with lilac highlights”. The only photo is a black and white one, showing the cats as having darker noses (not surprising, since the hair is shortest on the nose). These would seem to be lilac tipped, though by all accounts they were somewhat unexpected!
The Chinchilla's sparkling looks mean it is often associated with luxury, quality and class; Chinchillas are therefore used in advertising products which want to appear a cut above the rest.