Yorkshire Terriers, or Yorkies, are a breed of dog that are known for its small size and the changing colours of its fur. Yorkie puppies are all born with the same two colours, but as they age, the colour of their fur begins to change.
When Yorkie puppies are born, they are always black and tan. The combination of the colours varies by dog, however. Some dogs have more black fur than tan and vice versa. Yorkie puppies are never born with only one colour. For example, a Yorkie puppy may look completely black when born, however upon inspection, you will find some tan fur somewhere on the dog's body. As the puppies age, there are only four colours of fur, in some combination, that the dogs will have. These four colours are black, blue, tan and gold.
It is often difficult to notice the change in colour of a dog's fur because it happens gradually. Generally, when a Yorkie is around six months old, his hair will begin to change colours. It often takes until the dog is about three years old before he has his permanent hair colour. The deep black coat of a Yorkie generally begins to gradually lighten around this age; however, every dog is different and every dog matures at a different pace.
Most adult Yorkies have lighter colour fur than that of young Yorkies. An adult Yorkie's fur is typically more tan and gold than black. Most adult Yorkies have gold coloured heads and bodies that are primarily a blue colour. This blue colour often looks like silver or grey. After a Yorkie is approximately three years old, the colours of his fur most likely will not change.
Purebred Yorkies are known for having blue fur. The blue is not a bright blue, but more of a blackish-blue or a diluted black. This occurs because of a gene these dogs are born with. Yorkies are the only breed of dogs that carry this particular gene.