Many yorkies in Europe have their tails curved over the back or worse the tail touches the back, giving a shih tzu appearance, upsetting the outline. Personally I don't like it. I prefer a more straight tail. As far as I know this is a trait that many breeders trying to improve.
Genetically, according to a list of traits generally agreed to be either dominant or recessive, (Ann Seranne - The Joy of Breeding Your Own Show Dog) the straight tail is dominant and the kinked or bend tail recessive.
One other thing that I have noticed is that many dogs with undocked tails are prone to a brighter color at the base of their tail. I dont know if this has something to do with the distribution of eumelanin in this particular point, considering the tan which is underside. The tip of the tail is always a darker color in order to prevent the tan from invading to the blue area.
(The color of the skin on the upper side of the tail is blue and on the under side is pink).
I was wondering whether this has something to do with docked or undocked tails. For example when the tail is docked the color particles can be distributed more evenly in a smaller area. When the tail is not docked, the same amount of color particles have to be distributed in a larger area. Could this be the reason that many undocked dogs have a brighter color at the base of their tails?
Just wondering
As far as history is concerned, the first standard as published in the "American Book of the dog" written by P.H. Coombs in 1878, didn't mention the tail at all.
https://archive.org/stream/americanb...rch/yorkshire+
In the Stonehenge book " Dogs of the British Islands" the Yorkie article is written by Hugh Dalziel. He writes:
"Yorkshire terriers. In assessing the value of points, shape, coat, and colour absorb nearly all. I would, however, give ten points for ears, and five for tail, and
deduct points for cropped ears and docked tail; also for carriage of the tail over the back. There is no reason for mutilating pet dogs, and perfect tails and ears should be bred, not clipped into shape with scissors. Lady Giffard's Katie, in the engraving, has natural ears, and very good ones."
Katie and Huddersfield Ben seem to have undocked tails.
https://archive.org/stream/dogsofbri...arch/yorkshire
Here you can see Mrs Foster's PRINCE who also seems to have undocked tail
https://archive.org/stream/britishdo.../n541/mode/2up