I think the 'colors' are controlled by the "Y" chromosome...it may also contribute to the 'left/right' mutation!
Strangely, both mice seem to have the same colored tail!
BTW, can you reduce the size of your two largest images
Parker? Maybe decrease their original dimensions to something like 800 pixels wide? Then, swap those files with the really wide ones in your post. That will help prevent the annoying thread stretching caused by wide images. Apparently, with an extremely large image, even reducing by 70% doesn't create a small enough 'thumbnail'.
It is probably best to reduce an images resolution to ~72 - 100 dpi before posting to TS, unless you want to make an especially nice one available for downloading and printing.