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Canadian Amphibian and Reptile Conservation Network - Réseau Canadien de Conservation des Amphibiens et des Reptiles
Ascaphus truei
Tailed Frog
The Tailed Frog is a very unusual looking species. It has no external eardrum (tympanum) and the male has an external copulatory organ which appears to be a tail but is coloured similarly to the back. The colour varies from olive, gray or tan to almost black with dark spots on the back and a yellowish triangle on the head. The eyes have a vertical pupil. Maximum adult size is 5 cm.

The Tailed Frog is the only Canadian frog which does not call.

Confusing Species
Male Tailed Frogs can not be confused with any other species. While newly transformed froglets of most species may have a remnant tadpole tail, this true tail has a distinctly different colour and texture from the rest of the frog and is resorbed within a few days of transformation. The "tail" of the Tailed Frog extends from the base of the spine and has a colour and texture similar to the skin on the back of the frog. Spadefoots also have a vertical pupil but they have tympana as do all other frogs and toads.

Tailed Frogs are restricted to the southwestern mainland and areas north along the coast of British Columbia to Kitimat and Bella Coola. There are found as far south as northern California.

Tailed Frogs inhabit cold, swift mountain streams in steep sided valleys of forested mountain regions.

Tailed Frogs do not have a mating call. Mating occurs in spring or fall and eggs are laid the following summer in small clusters under submerged rocks. They remain tadpoles for two to four years and require a further eight years to reach sexual maturity.

Natural history
Adults eat aquatic and terrestrial insects. During the day they hide beneath rocks in the stream, emerging to forage in the evening. Tadpoles attach themselves to a rock with their mouth parts when they want to remain stationary in the swift current and scrape algae and other food from the surface of stones. Maximum known age is 14 years.

Conservation Concerns
The Tailed Frog has declined where its habitat has been degraded by logging. When trees are removed from adjacent to the stream, not only is foraging habitat destroyed but the increased exposure alters the water temperature and allows rain to wash soil into the stream. This species is considered vulnerable in British Columbia.

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