I have a 4.5 year old spayed female Boston Terrier. This Summer her dark brindle coat has been getting markedly lighter. Our friends and our vet have noticed it too. Lots of tan hair is coming through on her legs, hips, and sides. I seem to remember her getting slighly lighter in past Summers, but not like this.

Her diet and behavior haven't changed. She's got plenty of energy.

Anyone experience this with Bostons before? Just trying to figure out whether I should be more concerned.

Not a worry. Some dogs do go paler in Summer anyway.Others change colour as they get older, something which is a chacteristic in their genes.Some individuals get paler, some darker, several change shade to more reddish or more golden etc (not all as extremely as the silver poodles, all of which are born black and are only silver as adults, even then becoming slightly more silver over time!)