My 2 oldest sulcatas use to be completely different colors than each other.Tatsu is about an 18" shell and is that light tan color and about 3 years ago when i got my other one it was that dark dark brown color and was about 12" shell. Now is about 15" shell and is very close to the same color as Tatsu. I live by a river and my soil is very sandy and the same color as my torts shells are now. So my question to everyone is, do sulcatas shell change color with their surroundings over time or do the just get lighter with age. Should be fun to see what everyone thinks.