Two Frogs and a Toad

There are two species of frog and one of toad  in the vicinity of myllylähde. The reason for three species being found there is the spring itself, as it is an ideal wintering environment for frogs. Although there are few frogs in the ridge area due to the dryness of the environment, there are common around the springs on the ridge.


Frog spawn

The most common species of frog in the region is the common frog (Rana temporaria), which is difficult to distinguish from the smaller moor frog (Rana arvalis). The moor frog is smaller in size and has a sharper looking snout, but it is easy to distinguish from common frogs by checking the nodes on the inner soles of its feet. This node is soft and round on most frogs but is gnarly and large on the moor frog. The easiest way to distinguish between the common frog and the moor frog though is during spawning as the moor frog’s voice resembles the sound of a sinking bottle. The toad that lives at Myllylähde is the common toad, which has a dry skin and is completely covered with wartish lumps. Compared with other frogs, the toad is slow moving and it crawls rather than leaps.

Myllylähde attracts amphibians more in the autumn than summer. By the time of the first frost, the frogs will be winterong on the bottom of the spring. They usually dig under the surface, but sometimes they can be seen on the floor of spring ponds in winter time. The body temperature of the frogs remains around half a degree above the ambient temperature. However, they do not hibernate and may even move actively. Frogs fast for the whole of the winter season and because their metabolism is very slow, the oxygen they get straight from the water through the skin is enough. When the average air temperature has increased to about 5 degrees, the frogs leave their ponds and move to spawning places. However, frogs at Myllylähde are not likely to move as the it also functions as a spawning place.

Photo: Jyrki Oja