Our mystery neonatal canid is a newborn gray fox (Urocyon cinereoargenteus).
Both normal red and cross phase red foxes and gray foxes are born this ashy gray color. The way to tell the neonates apart is to look at the nails. Gray foxes have long, curved nails, which they utilize in their well-known arboreal habits. Gray foxes are so at home in the trees that some people call them “tree foxes.”
Of course, the other way to tell them apart is to look at their tails. All red foxes, regardless of phase, have white-tipped tails. Gray foxes never do.
I should note that I have some issues calling a gray fox a fox. They are not true foxes at all.
The two canids in the genus Urocyon are thought to represent a primitive line of the dog family that retained the ancestral carnivores’ ability to climb trees.