For your envisioning pleasure – and also because I secretly hope someone will send me fan art along the lines of a classic Old West painting set on said Mars-type world (beautiful for spacious pink skies and vermilion mountains’ majesty above its fruited plain of mottled green and blue grass, although the grain still comes in amber waves) – the greenlife quebérúr is a relative of the Terran bison. Specifically, it’s a separate descendant of Bison antiquus than our modern Bison bison, that has kept the 15%-25% larger size of the former (about 7.5′ tall, 15′ long, and 3,500 lbs.) Other relevant differences include having developed curled, downward-pointing horns, and being able to digest and mostly excrete the non-overlapping compounds across the bluelife/greenlife gap without being poisoned or sickened by them. Much the same parameters apply to their transbovine descendants.
Every bit as tasty, though!