The study of adaptive traits rarely has been applied toward the conservation of biodiversity. Fields such as evolution, biogeography, behavioral ecology, population biology, and genetics have facilitated conservation goals, but only partially and only for a few taxa. Among the world's most endangered mammalian families is the Rhinoceratidae whose five species are being exterminated for their horns. Numerous conservation actions have been applied to these species. The most radical, horn removal, is designed to improve the conservation of both black (Diceros bicornis) and white (Ceratotherium simum) rhinos. In this paper, I use basic and applied biology to suggest how science has or has not contributed to the in situ conservation of black rhinos. I make four points: knowledge about associations between mating systems and sexual dimorphism has helped illuminate the evolution of secondary sexual traits; relationships between behavioral responses of black rhinos to dangerous predators and subsequent mortality are of basic interest, but this knowledge has not abetted rhino conservation; prior literature indicates that the young of horned mothers regularly are maimed by dangerous predators (if horns have utility as defensive structures, then phenotypic alterations of female horns should increase the susceptibility of young to predation, a prediction with empirical support from a Namib Desert population); because wild populations of black rhinos have been depleted in the past 25 years by 97%, it makes little sense to plan how to conserve genetic diversity over the next 500. Science will continue to play a critical role in the future conservation of small, heavily managed populations. However, it is less likely to be of major significance in the in situ conservation of rhinos until sociological, economic, and political issues are effectively resolved. Keywords: conservation, science, predation, mating systems, black rhinos, spotted hyenas, Africa.