Systematic survey of mammalian skeletons has revealed patterns of disease reproducible over geologic time. Systematic examination of non-passerine bird skeletons also reveals patterns of disease and identifies those disorders amenable to epidemiologic assessment. Neoplasia, infection, osteochondromatosis and gout are extremely rare, precluding phylogenetic comparisons--at least those based on macroscopic examination of skeletons. Osteoarthritis, paradoxically, is identified at sufficient population frequency for meaningful investigation.