Why do Yorkshire terriers change color as they get older?

Yorkshire terriers are born black and tan. As they grow older, their coat lightens and changes to a steel blue and tan. This is due to a combination of genetics and environmental factors.

Genetics: The coat color of a Yorkshire terrier is determined by genes that control the production of melanin, the pigment that gives hair its color. Yorkshire terriers have two main color genes:

- The B gene, which controls the production of black pigment

- The E gene, which controls the production of red or yellow pigment

The interaction of these genes produces the characteristic black and tan coat of a Yorkshire terrier.

Environmental factors: The environment can also affect the color of a Yorkshire terrier's coat. For example, exposure to sunlight can cause the coat to lighten, while a diet rich in certain nutrients can help to keep the coat dark and vibrant.

The rate at which a Yorkshire terrier's coat changes color varies from dog to dog. Some dogs may start to change color as early as 6 months old, while others may not reach their full adult coat color until they are 2 or 3 years old.

Here is a general timeline of the color changes that a Yorkshire terrier may experience as they get older:

- Birth to 6 months: The coat is black and tan.

- 6 months to 1 year: The coat begins to lighten and change to a steel blue and tan.

- 1 to 2 years: The coat continues to lighten and darken.

- 2 to 3 years: The coat reaches its full adult color.

It is important to note that not all Yorkshire terriers will experience the same exact color changes. Some dogs may have a more dramatic color change, while others may have a more subtle change.