There are only six species of small frogs in this family. The frogs in the genus Ascaphus are referred to as tailed frogs and are found in North America. Until recently they were placed in their own family, Ascaphidae.

The frogs in this family have nine vertebrae in the front sacrum instead of the usual eight found in other frog species. (The sacrum is the triangular bone at the base of the vertebral column.)

The two species of North American tailed frog in this family are the Rocky Mountain tailed frog and the coastal tailed frog. They are found in the northwestern United States and southwestern Canada.

Tailed frogs are about 2 inches in length, and the male has what looks like a tail. The tail is part of the male frog’s reproductive system and is used to transfer sperm to the female.

Female tailed frogs fertilize their eggs internally. Tailed frogs can be brown, gray, or reddish. They live in swift-moving, cold mountain streams. Tailed frog tadpoles have sucker-like mouths that they use to attach themselves to rocks in rushing water! Male tailed frogs are smaller than female tailed frogs.

The four species of frogs in the genus Leiopelma are found in New Zealand and are the only frogs native to New Zealand.