The Tailed Frog Ascaphus truei

by Donna Hill B.Sc. B.Ed. 1997, up-dated 2005

The Tailed Frog is a protected species in British Columbia. It belongs to a primitive Family of frogs called Ascaphaidae that has a 'tail' it uses to internally fertilize the eggs. The tail is not a true tail since the cloaca opening is located at the tip of the tail. Other characteristics of this genus are that it has muscles to wag the 'tail', free floating ribs (which other frogs don't have) and its tongue is attached at the back of its mouth, unlike other frogs.

Tailed frogs can be recognized by their small size (up to 5 cm (2 inches) from tip of snout ot tip of tail), vertical pupils in their eyes, no visible eardrums and small bumps on their skin (called tubercles). They have fully webbed toes and females are slighly bigger than males. Tailed frogs make no known sounds.

Tailed frogs live in and near rock-strewn mountain streams that have cold fast-flowing water. These streams are usually located in un-disturbed forests as any silt that gets in the stream can kill the eggs and tadpoles.

In the fall of 1997, in West Vancouver, BC, some grade 5 students discovered Tailed frogs and their tadpoles in a local stream (McDonald Creek) where they were previously unknown. With the help of their teacher and biologists, they trapped and counted 2 adults and 164 tadpoles over a few days. They took this information to the municipal council to alert developers of their presence. Developers re-designed the housing area so the stream would stay intact and this ended up being a bonus to potential home buyers of the area. Individual effort does pay off!

In the autumn, the bumps on the sides and arms of the males thicken up and more bumps appear on the sides of the chest under the arms. This shows the females that the males are ready to breed. The eggs are not laid until the following summer when they are laid in long bead-like strings attached to the undersides of rocks so they won't be carried away by fast moving water.

The eggs hatch in late August, and the tadpoles are easy to identify since they are the only local tadpole to have a white spot at the tip of their tail. The tadpoles have a strong suction-like mouth that allows them to scrape algae and diatoms off the rocks and also grip tightly onto rocks so they too won't be carried away by fast water. Sometimes, they will crawl right over rocks (out of the water) in their search for food.

Tadpoles take two to three years to metamorphose (change) into frogs and will not breed until they are mature at about seven to eight years of age. Adults stay in the stream and on wet days will hop about in nearby wet forest floors looking for food.

Tailed Frogs are mostly nocturnal (night-active) in their search for both land and water insects and worms, even swimming under water to catch them!

Tailed frogs are found in pockets with proper habitat in the south-west corner of British Columbia (Lower Mainland, Sunshine Coast), western Washington and Oregon and the north-west corner of California.

Because this is a protected species in B.C., a special collection permit is needed from the BC Ministry of Environment as well as the usual B.C. vertebrate permit. You can be fined or jailed if you are caught collecting or keeping them (live or dead) without required permits.

These laws protect them so they can fill their role in nature forever and our great grand children can enjoy them as we do today.

Back to Research

Back to Habitats

Back to Wild Inside Home