What is the primary difference in selective pressure between a wild mouse and a fancy mouse?

Wild mice are shaped for caution and stealth, while fancy mice genetics are shaped by human preference for docility.

The selective pressures applied to wild mice and fancy mice are fundamentally opposed due to their environments and goals. Wild mice, such as *Mus musculus* in their natural habitat, face constant threats from predators, meaning their evolution is driven by traits that maximize survival in the field. This translates to a focus on caution, excellent camouflage (like the agouti color), and stealthy movement. Conversely, fancy mice are the result of centuries of human intervention and selective breeding aimed at domestication. The primary objectives for fancy mice breeders are temperament and appearance. Therefore, the genetic selection favors docility, approachability, and the development of varied aesthetic traits such as unique coat colors and patterns, rather than traits optimized solely for escaping natural predation.