The diminutive faefox began existence as a genetically engineered pet. These delicate, precious little creatures were bred from fennec foxes (chosen for their endearing qualities), with a smattering of red fox dna added to the mix (to improve colour). Measuring no more than 8 inches from nose to tail tip, they made charming pets. Omnivores, their main diet was fruit and vegetables, with the occasional egg thrown into the mix. They have a special sweet tooth for honey. After human civilisation fell, the faefox became feral, scampering up trees like a squirrel to evade the predatory advances of cats and dogs.
And here's my original fox evolution, an aardvulp: