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Pickerel Frog

Lithobates palustris

Family: Ranidae

Until recently, the Pickerel Frog was in the genus Rana, but it is now in the genus Lithobates.

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

Description

The Pickerel Frog can grow to 8 cm in body length and females are larger than males. Individuals are olive green, grey or brown with rows of dark, rectangular spots down the back and sides, bands on the hind legs, prominent, light cream or bronze-coloured dorsolateral folds (folds of skin running down each side of the back), a white belly, and bright yellow colouration on the thighs and groin. The dark spots on the back are arranged in two rows. Larvae (tadpoles) have long tails with a large fin and lack front legs (newly hatched tadpoles are legless). Larvae are brown to olive green with yellowish sides and have black and yellow speckles, a cream-coloured belly and a tail that is darker than the body. The larvae may reach lengths of 7.5 cm before metamorphosis. The call is a low-pitched snore similar to the call of the Northern Leopard Frog, but not as complex.

Similar Species

The Pickerel Frog may be confused with the Northern Leopard Frog, but the Northern Leopard Frog has oval spots that are randomly distributed on the body. The Northern Leopard Frog also lacks the yellow on the thighs and groin, which are instead white.

Distribution

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The Pickerel Frog is found in southern and eastern Ontario, southern Quebec, New Brunswick and Nova Scotia. This species also occurs throughout much of the eastern United States from southeastern Minnesota to Maine in the north to Georgia and eastern Texas in the south.

Habitat

The Pickerel Frog is usually found in forested areas and breeds in wetlands, lakes or large ponds that often have extensive emergent vegetation near shore. During the summer, individuals may disperse into streams, swamps and moist forest habitats, and they can be found a considerable distances from water. This species hibernates at the bottom of water bodies that do not freeze solid.

Biology

In Canada, Pickerel Frogs hibernate during the winter and are typically active from April until late September or October. Males call to attract females during the breeding season, which occurs over a short period in April or May. During breeding, the male grasps the female (amplexus) and fertilization occurs externally in aquatic habitats as the female lays eggs. The female lays a globular mass of 1000–3000 eggs that is 4–10 cm in diameter. The egg mass is usually attached to aquatic vegetation 7–10 cm or more below the surface of the water. The eggs are brown on one side and yellow on the other and are surrounded by two clear jelly envelopes. The eggs hatch in 1–3 weeks, depending on the water temperature. The larvae usually transform into frogs in 3–4 months, however some tadpoles in the northern part of the range may overwinter before transforming. Individuals reach maturity after 2 years and most probably do not live for more than 5 years. Individuals are active during the day and night and they eat a wide variety of insects, spiders and other small invertebrates. Pickerel Frogs may make long migrations between their hibernation and breeding sites.

Threats

The Pickerel Frog is uncommon or rare across most of its range. It is unclear if this is a result of a decline or whether it has always been spotty in its distribution. Habitat loss and degradation is a threat to this species, especially in southern Canada where much of the landscape has been converted to intensive agriculture and urban areas. Pollution, such as herbicides, agricultural effluent and road salt, can be detrimental to frog populations by causing direct mortality as well as developmental deformities. Large numbers of Pickerel Frogs are killed on roads every year during migrations to and from breeding sites, and high levels of road mortality can cause long-term decline of frog populations. Pathogens such as chytrid fungus and Ranavirus can cause mass mortality of frog populations. Climate change may also pose future threats to Canada’s frog populations.

Additional Information About This Species In Canada