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The Northern Leopard Frog (Rana pipiens) is a species of Leopard frog from the true frog family native to parts of Canada and United States.
Physical description
The Northern Leopard Frog is a fairly large species of frog reaching about 11cm in length. It varies from green to brown in dorsal colour with large dark circular spots on their back, sides and legs. Each spot is noramally borderd by a lighter ring. A pair of dorsolateral folds starting from the back of the eye run parallel to each other down the back. These dorsolateral folds are often lighter or occasionally pinkish in colour. There is also a pale stripe runnning from the nostril, under the eye and tympanum, terminating at the shoulder. The ventral surface is white or pale green. The iris is golden and toes are webbed.
Ecology and behaviour
Northern Leopard Frogs inhabit a wide range of habitats. They are found in permanent ponds, swamps, marshes and slow moving streams throughout forest, open and urban areas. They noramlly inhabit water bodies with abundant aquatic vegetation. They are well adapted to cold and can be found above 3000m asl. Males make a short snore like call from water during spring and summer. Up to 6500 eggs are laid in water and tadpoles complete development within the breeding pond. Tadpoles are light brown with black spots and development takes 70-110 days, depending on conditions. Metamorph frogs are 2-3cm and resemble the adult.
This species was once quite common through parts of western Canada until declines started occuring during the 1970's. The decline is thought to have been caused by pollution drift from the United States falling in the form of acid rain. Many populations of Northern Leopard Frogs have not yet recovered from these declines.
Northern Leopard Frogs are preyed upon by many different animals such as snakes, racoons, other frogs and even humans. They do not produce distasteful skin secretions and rely on speed to evade predetation.
This species is similar to the Pickerel frog (Rana palustris) and the Southern Leopard Frog (Rana subaquavocalis).
References
"Northern Leopard Frog"