A hard decision. What entails the word "feral," and what comes to mind from the word? Is it a carnivore, omnivore, or herbivore? Even though the word is synonymous not with diet, but whether or not it is domesticated.
Personally, I am torn between a cervine and equine. Both of which are often created now, despite the limitations. Though, just because their real-world counterparts are strictly herbivorous (even though, the will to survive may warrant some questionable consumption of meat) doesn't mean they should be restricted to such in-game.
However, it can also be all of the above! Perhaps, over time.
Other possibilities, variants of the canine and feline model; wolf vs dog, big cat vs house cat.