The Coastal Tailed Frog – a key species in the Great Bear Rainforest

Publication - September 14, 2010
The coastal tailed frog is a relatively small frog which has a long life-span, and is uniquely adapted to life in the cool, fast-flowing mountain streams of the coastal temperate rainforests.

These tiny frogs — approximately three centimetres long — have reduced lungs and breathe mostly through their grainy-looking skin. It is theorized that because they live in the relatively loud environment of constantly flowing streams, they are voiceless. The most outstanding physical feature of the coastal tailed frog is its tail. Found only on adult males, the tail is used for internal fertilization and is an adaptation that ensures that sperm reach the eggs rather than being washed downstream.

Coastal tailed frogs live in cool, clear mountain streams which flow throughout the year. These frogs also thrive in old-growth forests that are adjacent to these cool, fast-flowing streams. They are slow to reproduce and are very sensitive to changes in the conditions in and around their home streams. As such, industrial scale logging is especially of concern in terms of impacts to their habitat. Logging removes cover vegetation, leads to a drier and harsher terrestrial environment, an accumulation of silt, disturbs streambeds and increases water temperatures. Siltation is particularly problematic because silt fills the spaces between rocks that are essential for feeding, egg-laying, over-wintering, and for refuge from potential flooding.

Much of the coastal tailed frog’s natural habitat has been altered or destroyed by logging (and by urbanization in the more southern parts of its range). Although current forest practice requirements in the Great Bear Rainforest provide protection for fish streams, this is not the case for streams that the tailed frog relies on. Future run-of-the-river projects may also threaten coastal tailed frog habitat.

Coastal tailed frogs are listed as a species of special concern by the B.C. Conservation Data Centre (blue-listed) and by the government of Canada.

SOME INTERESTING FACTS

  • Adult coastal tailed frogs need to stay moist as they do no tolerate drying the way other frogs can.
  • Though they may move away from the place where they hatched, once they have chosen a stream as adults, coastal tailed frogs usually will live close to that ‘home’ stream for the remainder of their lives.
  • Coastal tailed frogs may live 15 to 20 years – one of the longest life-spans among all species of frogs in the world.
  • The coastal tailed frog is not able to flip out its tongue to grab insects the way other frogs can. It jumps on its prey and takes it in with its mouth.
  • Coastal tailed frogs cannot call as they are voiceless. And they do not have eardrums, though it is thought they can sense vibrations in water as a way of detecting prey or threats they cannot see.

SOURCES

ForestEthics, Greenpeace, Sierra Club BC, 2010. “Falling through the cracks? The fate of focal species in the Great Bear Rainforest.” Online at: http://www.savethegreatbear.org/files/gbr_species_report_mar2010

Government of British Columbia – Ministry of the Environment B.C. Frogwatch Program, online at: http://www.env.gov.bc.ca/wld/frogwatch/whoswho/factshts/tailed.htm

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