Columbia Spotted Frog
|Common Name:||Columbia Spotted Frog
|Scientific Name:||Rana luteiventris
At a Glance
The Columbia Spotted Frog and the Oregon Spotted Frog (Rana
pretiosa) were long considered members of the same species. While tough
to tell apart, these two frogs have non-overlapping ranges (live in
different areas) and can be identified by where they are found.
The Columbia Spotted Frog is a medium-sized frog with irregular black
spots, usually light-centred, on the head, back, sides and legs. Adult
frogs can be green, brown or reddish-brown while juveniles are brown or
olive green. Two dorsolateral folds (ridges of skin) run from the frog’s
head partway along the back. The eyes are set so that they are angled
slightly upwards, like those of the Oregon Spotted Frog. Undersides tend
to be cream-coloured with mottled reddish or salmon-coloured
pigmentation on the lower abdomen and hind-legs, but can also be yellow
in some populations. Adult females are slightly larger than the males
and can grow to a length of 5 to 10 centimetres (snout to rump). Webbing
on the feet extends to the ends of the toes. Tadpoles are dark brownish-
green, with gold flecks above and iridescent yellow to bronze below.
Intestines are visible through the skin, and the broad-finned tail is
often twice the length of the body.
The Red-legged Frog looks somewhat similar to the Columbia Spotted
Frog. However, the Columbia Spotted Frog tends to crouch to the ground
rather than sit up straight as the Red-legged Frogs does. Red-legged
Frogs also have eyes that angle outwards, flecks rather than spots, and
brighter legs than the Columbia Spotted Frog. The webbing on their feet
does not extend to the end of the toes.
Home Sweet Home
Rarely found far from water, Columbia Spotted Frogs make their
homes in or near permanent lakes, ponds, slow-moving streams and
marshes in a wide variety of wetlands, forest types, grassland, sage
brushland and even alpine tundra between 950-2000 metres above sea
level. Water bodies deep enough that they do not freeze on the
bottom are required for over-wintering of adults, juveniles and
possibly larvae. Shallow wetlands are preferred for other seasonal
activities. Columbia Spotted Frogs prefer thick algae and abundant
aquatic vegetation for cover and like to hide in rushes, sedge and
This is the Life
As ice melts from lakes, ponds and marshes keep your ears well
tuned, and you might be lucky enough to hear the soft call of the
Columbia Spotted Frog. Often heard only during the breeding season,
the call consists of a weak series of 6-9 clucking noises, like
clicking your tongue against the roof of your mouth. Males form groups
while floating near the water’s edge and call for females, who arrive
a day or two later.
Courtship and egg-laying take place in the
water, and eggs are laid in the vegetated shallows at depths of 3 to
30 cm. Deposited in spherical clusters of jelly about 15 cm in
diameter, these clusters float freely in the water and can contain up
to 1500 eggs! Larvae usually metamorphose (become adults) in a single
year, but in northerly populations, larvae will overwinter as tadpoles
and mature into adults the following year. Males may take up to 2-4
years to reach sexual maturity, while females may not breed until
their fifth or sixth year. A typical lifespan of the Columbia Spotted
Frog may be 10 years or more.
Columbia Spotted Frogs can complete
their entire life cycle in or near the same lake or pond, but will
also migrate seasonally and use different water bodies for breeding,
summer feeding and overwintering. This migrating habit makes these
frogs particularly sensitive to habitat fragmentation, such as road
building, which makes it tough for frogs to safely move from place to
What’s on the Menu?
Columbia Spotted Frogs serve up a wide variety of land and aquatic
insects, snails, crustaceans and spiders. Larvae munch on algae and
organic debris, and in turn provide an important food source for hungry
dragonflies, diving beetles, garter snakes and fish. Adult Columbia
Spotted Frogs may be eaten by River Otters, Raccoons, herons, garter
snakes, introduced Bullfrogs and trout.
Where and When
The mountainous regions of Alberta and most of B.C. are home to
the Columbia Spotted Frog. In the breeding season these frogs can be
found along the margins of permanent water bodies. In summer, adult
frogs are most active by day and will forage on land, but never stray
far from water. In the winter months, Columbia Spotted Frogs hibernate
by burying themselves in the muddy bottoms of lakes and ponds that do
not freeze to the bottom.
How Are They Doing?
With a fairly wide geographic range in Canada, the Columbia Spotted
Frog is one of the most commonly seen amphibians. However, little is
known about the sizes or trends in this frog’s Canadian populations. As
a ‘habitat generalist’, this frog feels at home in many different
wetland habitats in B.C. This means that if one kind of habitat is
disturbed, there are still several other kinds of habitat to live in.
However, because it takes such a long time for the Columbia Spotted Frog
to reach an age where it can reproduce, this species may be particularly
sensitive to population disturbance. This species is on the provincial
Yellow List of species managed at the ecosystem level.
The Columbia Spotted Frog is protected under the British Columbia
How You Can Help
Conservation of wetland habitat is essential for the continued
abundance of the Columbia Spotted Frog, which could be affected by
habitat loss and degradation, predation by introduced species and
the potentially negative effects of rising UV radiation levels. Get
involved with wetland conservation programs such as Wetlandkeepers,
Naturescape and Wild BC, and find out how you can help protect
B.C.’s precious wetlands by monitoring a pond or lake near you. Keep
your eye out for the Columbia Spotted Frog and other amphibians
where you live and share your observations with B.C. Frogwatch. These
observations help inform biologists of the range, distribution and
habits of amphibians in B.C.
- Because the Columbia Spotted Frog lacks an amplifying vocal sac, male mating calls are so weak, they only carry 15-30 metres. If Pacific Chorus Frogs were calling simultaneously, the calls of the Columbia Spotted Frog would be lost in the shuffle.
- Although in southern or lower elevation parts of their range, tadpoles of Spotted Frogs may grow very rapidly, developing limb buds and growing up to 36 mm in about 30 days, in more northerly or higher elevation populations, they may overwinter as tadpoles and metamorphose the following year.
Photo © Wally Edwards. No reproduction or distribution without permission.