WILLAPA BAY - Willapa National Wildlife Refuge staff discovered three tailed frog tadpoles on March 8 during a snorkel survey for fish in the upper reaches of Headquarter's Creek, the stream located near the refuge office.
Three additional tadpoles were discovered there on March 17. The addition of this species brought to 14 the number of amphibian species that have been documented on the Willapa National Wildlife Refuge.
The tailed frog (Ascaphus truei) is the most ancient species of frog in the world and is found only in the Pacific Northwest. (A separate genera in the tailed frog family occurs in New Zealand.)
This specialized frog occurs in cold and clear fast flowing streams. These streams generally have cobble or boulder substrates and contain little silt. The tadpoles have adapted to their fast flowing stream environment by having a huge sucker-like mouth that is used to cling to rocks. Because of their cold water environment, tailed frogs develop extremely slowly and are usually two to five years old before they metamorphose. Juvenile tailed frogs then take several additional years to sexually mature.
Tailed frogs, which are mostly active at night, are unusual in that they have eyes with vertical pupils. Males have a short "tail" that is used for internal fertilization of the female. The tailed frog is the only frog species that internally fertilizes its eggs. Tailed frogs are usually tan, brown or gray in color but sometimes can be green or red. They often are mottled with distinct dark blotches. A light triangular area can be seen between the eyes and snout. Females can be up to 2 inches in length and males to 1-3/4 inches.
Unlike most other frog species, tailed frogs do not call. In fact, a vocal sac and both the external ear and middle ear bone do not exist. These are most likely adaptations to living with the noise of a rocky stream environment where sounds are not important to the frogs during their life history.
Tailed frogs have previously been documented in other areas of Pacific County including the Ellsworth Creek drainage in the Nature Conservancy's Ellsworth Creek Preserve. They may be reduced in number or eliminated in some areas due to increased sedimentation in streams and increased stream temperatures in areas of timber harvest, or due to road building activities.