1any of a number of mammals or birds having a tail marked with a ring or rings, in particular. a ring-tailed cat or lemur. a female hen harrier or related harrier. a golden eagle up to its third year. 2 (also ringtail or ring-tailed possum) a nocturnal tree-dwelling Australian possum that habitually curls its prehensile tail into a ring or spiral.
- Genus Pseudocheirus and other genera, family Petauridae: several species, in particular the common ringtail (P. peregrinus), of southern Australia and Tasmania