Though just about all Yorkies will be black and tan as pups and blue and gold as adults, there are some Yorkshire Terriers that appear to be or that are mostly or fully tan. How can this be? There are a few different reasons. This section will discuss this, along with photos.
Reason #1 - Appearing All Tan, But Not Really
The first explanation is the easiest and the most simple.
When viewed from just one particular angle, a Yorkie may appear to be fully tan, as in the case of this little cutie pie (photo left, photo 1 on mobile). This is because the face, chest and legs are tan. However, with blue just on the back, when we gain a different angle of seeing the same dog (photo 2), it is then that you'll realized he is only partially tan, which is the typical coloring for this breed.
Photos 1 & 2: Oliver Wellington, courtesy of Lex & Rick
Reason #2 - Appearing Mostly Tan, Short Coat
Since this breed can have avariety of hair cutsand one of them is the very close-to-the-skin shaved puppy cut, when the coat is trimmed very short, this can remove a lot of the darker hairs.
When a Yorkshire Terrier has a medium or long coat, those dark hairs (blue or black) are going to really stand out and it is normal for the eye to be drawn to darker colors.
However, as you can see from this photo of King (right; below on mobile), when the coat is cut to a short 1/4 to 1/2 inch length, there is much less blue to focus on.
The tan essentially takes over, as far as the eye is concerned and since blue is a faded color, it really blends into the light tan.
King, 7 years old, photo courtesy of Lee
If this Yorkie were to have his coat grown out, his coloring would appear to be completely different. Though, his 'real' coat colors would not be changing; genetically, they are what they are. However, the length of those hairs can really change the dog's appearance.
So, if someone were to say, 'This Yorkie doesn't have the correct amount of blue or black', they would be very mistaken.
Reason #3 - Losing a Lot of Black as He Grows
The photo here (below on mobile) shows how a Yorkie can have a coat holding a majority of black as a puppy, but as that dog matures, a lot of the dark color is lost and simultaneously transitions to a blue.
So, here, you have an adult Yorkie that is mostly tan.
He holds the correct colors for the breed, however he changed as he matured..
Truffle, as a puppy and then as a 2 and 1/2 year old dog
Photos courtesy of Deborah
In addition, you'll notice that the long tan hairs on the back flow over the darker hairs, which lends to the over-all impression of being majorly tan
Reason #4 - Yorkshire Terriers That Are Truly All Tan with No Black
The last reason, though rare, is possible with this breed.
Though just about every single Yorkie is born black and tan (99%) and that black changes over to blue as they mature, therearesome 100% purebred Yorkshire Terriers that are fully tan as adults. This is the exception, never the rule, just as there are sometimes, rarely, those that are black and red as adults (known asred legged Yorkies).
Bear, a fully tan Yorkshire Terrier, whose black/blue grew out as he grew up! Photos courtesy of Alexandra Goldy
For all Yorkies, the darker hairs will cover far less
of the body than when the Yorkie was a puppy. Present on 60 to 90% of the coat during puppy-hood, it often ends up most prevalent on the back as an adult.
So, as the coat is morphing, more tan is coming in, darker hairs are falling out and fading.... and for some Yorkies, the tan overtakes the coat.
While this is considered a fault in show and Yorkies with these coats should not be bred, this is a random even that does not affect the dog in any other way aside from anesthetics (and it can't be denied that Yorkies with all tan coats are cute). And it is not caused by 'bad' shampoos or by too much brushing
or any such thing.
It is not even caused by bad breeding practices (unless a breeder purposely breeds a fully tan Yorkie to another that holds mostly tan).
It is simply a genetic color marker that can appear without warning and will not often even be visible until that pup matures. It can take 1, 2 or even 3 years for the black to fully disappear.
You may be wondering if darker hairs can ever grow back in. Frankly, while there may be some odd, random occurrence, in general this cannot happen.