Mars

Mars is the Roman god of war, whose name is of uncertain origin — possibly from an Etruscan root or from Latin mas/maris (male, virile). As the fourth planet in the solar system, Mars is the closest to Earth in appearance and was long associated with battle, fire, and red-tinged intensity.

Mars is a name with celestial authority. Short, one syllable, completely unambiguous — it says exactly what it means, which is that this pet has a certain force of presence that you noticed right away. The red planet association works beautifully for rust-colored, orange, or red-coated animals, while the god-of-war mythology suits dogs who carry themselves with an earned confidence. Mars is also gaining momentum as a human baby name, which means that pet Marses are ahead of a naming curve that is only going to get more interesting.