boxer changing color

Question
Hi,I have a fawn colored two and a half years old. On his underbody and inside the back legs, his white color is changing to a dark color. I dont think anything is wrong with him,but just wandering why.  
                        Thank You

Answer
As they age, the skin coloring changes. It's hormonal.

My female Boxer has undergone skin color changes through the past two years.

She is now dark on her inside thighs, but her stomach is still pinkish-white.

I wouldn't worry unless their are lesions, rashes, moles, etc. that would be s sign of cancer.