Hi, Robin!

That is a cute rat - IIRC, the Himalayan gene is recessive, and its expression is thermally controlled. (The points are darker because they're cooler.) I've got himalayans (without tanned butts) in my colony - including some dumbo rexes that I recently held back. As fuzzies, they're often whitish over the front half of their bodies, and dark on the back half - the front half is kept warm while nursing under momma's belly, while the exposed back half is cooler! I've read that a good outcross for the Himalayan gene is to a self black, which help with the intensity of the points.

Enjoy working with her!

~Bruce