Nuna were diminutive bipeds, mostly covered in scaly skin and sporting a distinctive dorsal ridge. They came in a variety of shades, ranging from greens to browns, depending on the subspecies. They possessed a notably prominent jutting jaw and two large wattles hanging from either side of their mouths. They had large three-toed feet which were quite massive with respect to the rest of their bodies. Though the nuna were flightless, their skeletons were birdlike, as evidenced by a large keel-bone and pelvis. Distinctively, they featured a large anterior body cavity that could inflate the nuna when agitated. A dwarf sub-species existed, the adult of which was approximately the same size as a chick of the common species.
Nuna often exhibited awkward behavior, running with more of a waddle than a stride on their long legs. When vocalizing, a nuna's wattles erected outwards from their face. When angered or agitated, the nuna could inflate its body to a strikingly larger size. Nuna survived on a primary diet of swamp plants, though they exhibited opportunistic omnivorous behavior, occasionally eating amphibians. Although they were non-aggressive, they could effectively defend themselves with kicks from their powerful clawed legs when cornered. Nuna also exhibited a high reproductive rate, laying considerable batches of eggs that also acted as a decent fertilizer if not hatched.