Tailed frogs are unique in the fact that they have a tail that they use for reproductive purposes, making them the only two frogs in North America to reproduce internally. This is useful for the frogs because they often live in fast flowing that would wash the eggs away before they would be fertilized. Tadpoles of the family have suckers on their mouth to hook onto rocks so they don’t get washed down stream. Tadpoles take on average four years to metamorphose but they can take up to eight years.
The members of the family Ascaphidae are found in the Southwest of Canada and the North Western United States, from the west coast to the Rocky Mountains. The Tailed Frogs are part of the suborder Archaebatrachia which are the most ancient linage of frogs. Some of the more primitive traits of the family are that the males don’t vocalize and they have nine pre-sacral vertebrae (advanced frogs have less).