Columbia Spotted Frog / Grenouille maculée de Columbia
The Columbia Spotted Frog is a large brown true frog with ill defined spots which may have light
centres. It has dorsolateral ridges
and a dark mask with a light stripe on the upper jaw. Its toes are fully webbed and the
eyes are slightly upturned. The
tympanum is prominent. The underside may be yellow, orange or red with dark mottling
on the throat. Maximum adult size is 10 cm. The two species of Spotted Frogs are very
similar and very closely related. It has only recently been recognized that they are
two different species. The Columbia Spotted Frog differs from the Oregon Spotted Frog
in having a larger head. In Canada, Columbia Spotted Frogs do not have mottling at the
throat although they do in the United States.
call is a series of short, rapid grunts which build in intensity. The entire
call may last up to ten seconds. It is not known if the call differs between the
The Columbia Spotted Frogs may be confused with Northern
Red-legged Frogs which differ in having incomplete webbing on the toes and not having
upturned eyes. Northern Red-legged Frogs are always yellow beneath with red wash on the
underside of the legs and the belly. Northern Leopard
Frogs have much more distinct dark spots with light rings around them. The other true
frogs found within its range do not have spots.
In Canada, the Columbia Spotted Frog is found in mountainous parts of western Alberta and
eastern British Columbia as far north as Carcross in Yukon Territory. The range extends
south into the northwestern United States.
Spotted Frogs are found in permanent water in alpine and subalpine areas with
mixed coniferous or subalpine forests.
Breeding occurs early in spring and egg masses are laid communally with each consisting of
700-1,500 eggs. They hatch in about four days. Larvae may transform by the end of summer or
overwinter as tadpoles and transform the following year. They may take up to six years to
Spotted Frogs are primarily aquatic and when frightened will swim to the bottom
and remain still. Differences in natural history between the two species have not been
The Columbia Spotted Frog has declined in Alberta as a result of urbanization. There is no
evidence of decline in British Columbia.