The relict leopard frog, Rana onca, has not been found in Utah since 1950. In fact, the species was believed to be completely extinct until three populations were found in Nevada during the early 1990s. The relict leopard frog formerly occurred in Utah along the Virgin River near St. George in Washington County. Biologists are not sure why this species became extirpated from Utah, but dewatering of the Virgin River, hybridization and competition with introduced frog species, and predation by non-native bullfrogs and fishes are all possible explanations.
Because so few relict leopard frogs have been found, little is known about their feeding and reproductive habits. Adults probably eat insects, whereas tadpoles likely eat plants, detritus, and algae. The species may breed in the spring, but exact times are unknown.