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Columbia Spotted Frog

Rana luteiventris

Family: Ranidae

COSEWIC status:
  • Not at Risk
SARA status:
  • No Status
IUCN status:
  • Least Concern

Description

The Columbia Spotted Frog is a medium-sized frog that can attain a body length of up to 9 cm, with males being smaller than females. Individuals are tan, light to dark brown, grey or olive-green and they have distinct light-centred dark spots on the back. The underside of juveniles is white to cream-coloured but it becomes yellow, orange, red or salmon in adults. Individuals have smooth skin with small bumps, upward-angled eyes, dorsolateral folds (folds of skin running down each side of the back) that often break up part way down the back, and extensive webbing that reaches the end of the toes on the hind feet. Larvae (tadpoles) have long tails with a large tail fin and lack front legs (newly hatched tadpoles are legless). Larvae have a tan, dark brown or greenish body and tail with gold and bronze flecking, dark spots or flecking on the tail fin, and a white to cream belly. The larvae can reach 10 cm in length before metamorphosis. The call of Oregon Spotted Frog is a rapid series of short, low-pitched clucks of increasing intensity.

Similar Species

The Columbia Spotted Frog may be confused with the Oregon Spotted Frog and the Northern Red-legged Frog. The Northern Red-legged Frog has semi-translucent skin on the underside of the hind legs, lacks the upward angled eyes, and the webbing on the hind feet does not extend to the tips of the toes. The distributions of the Oregon and Columbia Spotted Frogs do not overlap, so these very similar species can be differentiated based on location.

Distribution

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In Canada, the Columbia Spotted Frog is found in the southern Yukon, southwestern Alberta and throughout most of British Columbia with the exception of the southwestern coastal areas and the extreme northeast corner of the province. In the U.S., this species occurs from central Washington and Oregon east to western Montana and Wyoming and south into Nevada and Utah.

Habitat

Columbia Spotted Frogs inhabit and breed in wetlands, lakes, ponds, streams or other permanent aquatic habitats. Aquatic habitats typically have shallow, warm areas and abundant floating or emergent vegetation. Columbia Spotted Frogs are highly aquatic but will venture into nearby terrestrial habitats to forage during the summer, and juveniles can make extensive terrestrial migrations. Individuals hibernate underwater in deeper parts of wetlands, lakes or streams.

Biology

In Canada, Columbia Spotted Frogs hibernate during the winter and are active from March or April until October or November, depending on latitude and elevation. Male Columbia Spotted Frogs call to attract females during the breeding season, which occurs in the early spring, immediately after ice recedes from the wetlands. During breeding, the male grasps the female (amplexus) and fertilization occurs externally in aquatic habitats as the female lays eggs. The female lays 250–1,500 eggs as a large gelatinous mass that is attached to aquatic vegetation just below the water’s surface. The eggs are dark brown to black on top and pale yellow to light tan underneath and are surrounded by two clear jelly envelopes. The eggs hatch in 2–4 weeks and larvae usually transform into frogs 3–4 months after hatching, but individuals in colder climates may overwinter as larvae before transforming. Males reach maturity at 2–4 years of age and females do not mature until they are 4–6 years of age. Individuals can live for over 10 years. Columbia Spotted Frogs forage on land and in water for a wide variety of invertebrates, including spiders, insects, sow bugs and snails.

Threats

The Columbia Spotted Frog occurs throughout large expanses of British Columbia that are relatively undeveloped, and threats to this species are minimal throughout most of its range. Habitat loss, primarily from urban development, agricultural expansion and logging, can result in local population declines and extirpation. Pesticides/herbicides, road salt, sedimentation from forestry activities, and other environmental pollutants can be detrimental to frog and toad populations by causing direct mortality as well as developmental deformities. Introduced invasive species, particularly the American Bullfrog, are also contributing to declines in some areas. Pathogens, such as chytrid fungus and Ranavirus, can cause mass mortality of frog and toad populations. Climate change may also pose future threats to Canada’s frog and toad populations.

Additional Information About This Species In Canada