males calling from the edge of ponds and swamps from April to July. The call has been described as "a deep, low-pitched, rolling snore". The eggs are laid in a floating layer among emergent vegetation, a clutch numbering several thousand eggs which hatch after about three days. The tadpoles are at first a dark color but become much paler over time with a dark edge to the tail fin. They congregate in the shallows in the daytime, sometimes in dense swarms, but move into deep water at night. They feed on both animal and vegetable matter. They remain as tadpoles for a long period, overwintering once or twice, and reaching a snout-to-vent length of or more. After metamorphosis, the newly emerged juveniles are long and move away from the margins of the water. The large number of juveniles compared to the relatively small number of adults indicates a high mortality rate for newly emerged young. Predators that feed on tadpoles and juveniles are thought to include the banded water snake (Nerodia fasciata), other water snakes (Nerodia sp.), the largemouth bass (Micropterus salmoides) and the grackle (Quiscalus sp.). However the skin may contain some noxious substances or malodorous secretions as some snakes, including the indigo snake (Drymarchon), have been observed gagging and retching after eating a river frog. Even after the frog has been regurgitated, the snake continued to wipe its mouth on the ground. Status The river frog has a wide range and is quite common in much of that range. The population appears to be large and reasonably stable and the main threat the frog faces is degradation of its habitat; it has declined in portions of its range due to this, and is thought to have been extirpated from the northernmost extremity of its range in southern North Carolina by 1975. However, it is present in a number of protected areas and the IUCN considers its conservation status to be of "least concern". References (2005): Phylogeny of the New World true frogs (Rana). Mol. Phylogenet. Evol. 34(2): 299–314. PDF fulltext. (2007) Constraints in naming parts of the Tree of Life. Mol. Phylogenet. Evol. 42: 331–338. Amphibians of the United States Amphibians described in 1924 Endemic fauna of the United States Lithobates Taxonomy articles created by Polbot