I have noticed this color changing the frist time with my Donna, a grey cat. First the fur was shining red-brown in the sun only, the older she became the more you could see it. First I thought it is just because her mother Mietzi was a brown tiger but then I have asked the vet and he said, too it could be a diet problem but he believed it was Rufismus, a genetic defect that mostly appears with black cats but can also happen to other fur colors. Willi had the same fur color changing but not so much just like Paulinchen and Moritz's fur now changes as much as Donna's did. So I guess the vet's diagnosis was right because Donna, Willi, Paulinchen and Moritz descend from one cat, Mietzi.

Does anyone think that maybe grey fur "bleaches" out to brown in the sun? Any graphic artists? Is brown lighter than grey? It kind of looks to me like the discoloration is lighter than his grey.

I'm keeping an eye on him, because a quick Google suggests a diet problem could possibly cause this. But the other cats aren't showing anything unusual.

Well, look at the next pic pf Moritz and his gray fur shining brown now. The first 10-12 years of his life there was no brown at all.

Mark-that is really interesting. Iggy, who is grey and white also was ill recently and after he returned from the vet, some of his white fur has started turning a peachy color, actually a little rusty on the feet. What's up with these cats?

The top of Storm's head is starting to turn brown, as if he's trying to match his older brothers!