The selective advantage of coat color for concealment and regulation of body temperature likely caused geographic variation of coat color as well. For both concealment and body temperature regulation, the mice better adapted to their environment will likely survive better and produce more offspring. This means that the mouse that blends in with its environment the best, in a way that uses the least amount of energy will have a selective advantage. Going along with this, mice in different environments require different coat colors to blend in most effectively. Geographic variation between environments is another selective pressure that helped color polymorphism evolve between pocket mice. Pocket mice that live in sunny environments with an abundance of sand will have a selective advantage with light colored yellow or brown coats. In contrast, pocket mice that live on rocks in environments with less sun are more likely to have a selective advantage with darker colored grey or black coats.