Fox as a pet name is doing several things at once: it's a description of color (red-orange, bushy tail), a personality type (clever, quick, slightly unpredictable), and a reference point in both folklore and pop culture that spans centuries. It's a one-syllable name that carries more weight than almost anything else at its length.
Animal Symbolism in Pet Names
Naming a dog after another animal is a well-established move in pet naming — Wolf, Bear, Tiger, Fox. The fox specifically has a rich symbolic history across cultures: cunning in Aesop's fables, a trickster figure in Native American folklore, the clever protagonist in countless European fairy tales. Fox the pet name borrows all of that without requiring any of it to be stated. It just lands with a particular energy.
Pop Culture Dimension
Fox Mulder from The X-Files is the most famous fictional human Fox, and his combination of obsessive intelligence and romantic conviction maps surprisingly well onto certain breeds. Corgis with their fox-like faces, Shiba Inus (which physically resemble foxes), and Fox Terriers are the obvious breed matches. The human name Fox is genuinely rare on baby charts, which keeps the pet version from feeling derivative.
Sound and Visual
One syllable, hard F opener, the OX ending that closes decisively. Short enough to function as a command-length name, memorable enough to stand out. Fox skews strongly male in registry data but is not exclusively so — a female red tabby named Fox has complete internal logic. Compare with Vixen for the female-specific version of the same animal reference.