The Northern Frog 



North American species of Rana. From some such form might 

 have come all of our frogs, except, perhaps, the black-cheeked 

 ones, such as Rana sylvaiica, Rana draytonii, and the like. It 

 shows close relationship to the Green Frog {Rana clamiians) and 

 to the Bullfrog {Rana cateshiana). 



The Northern Frog is described as decidedly a river frog; 

 it is never captured in lakes and ponds. It is silent and unob- 

 trusive, solitary in habit, and thoroughly aquatic. We do not 

 see it in meadows or woods, but if we walk along the brook 

 margin or river bank, it will dive into the water, much as does 

 the Pickerel Frog {Rana palustris) in a similar situation. It 

 hides under stones, among water-plants, or in the mud near 

 the centre of the stream, and may not return to the surface for 

 fully a half-hour. In this habit of remaining long under water 

 when frightened, it resembles the Common Leopard Frog {Rana 

 pipiens). When it does appear, just head and shoulders are 

 thrust out among the water-weeds at the border of the stream. 

 The Northern Frog eats water-insects, and sometimes small 

 fish. 



The breeding-season is in June and July.* The egg-masses 

 adhere to water-plants, and wave back and forth with the cur- 

 rent half-way between the surface of the water and the bottom. 

 Two years are required for the development and metamorphosis 

 of the tadpole. The full-grown tadpole with developing legs 

 may measure four inches in length, two and one-half inches 

 being the measurement of the tail. The tadpoles are the scav- 

 engers of the brooks and rivers. For instance, they will greedily 

 eat a dead brook-trout, leaving only a perfectly cleaned skeleton. 



Both the frogs and the tadpoles give off a strong, disagree- 

 able odour when annoyed. This odour is said to be like the 

 scent of the mink, and this species of frog is often called the 

 Mink Frog. 



1 June 24 and July 30, 1883. Dr J. H. Gamier, Lucknow, Ontario. 



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