Ascaphus

The genus Ascaphus includes the tailed frog, a species native to the cold, clear forest streams of the Pacific Northwest in the United States and Canada. The "tail" on the male is an extension of the cloaca, used to transfer sperm directly to the female in fast-moving water. Breeding occurs in the fall, with sperm stored until the following summer for egg fertilization. The eggs require about two months to hatch in cold streams, and the tadpole stage can last up to three years, with adults reaching sexual maturity at seven or eight years. The genus is sometimes classified as its own family, Ascaphidae, or included within Liopelmidae.12