Vie larvaire des ouaouarons Rana catesbeiana Shaw (Amphibia Anura) des Laurentides, Québec

The 8908 tadpoles of Rana catesbeiana used in this study come from three lakes of the Laurentian region, north of Montreal (45°52′ N, 74° W). Histograms of body length and various morphometric data taken on the subjects revealed a few aspects of their biology. The majority of tadpoles undergo metamorphosis after two winters, and the remainder, in variable number according to the years, after three winters. Body length is approximately 4 mm 10 to 15days after spawning; it varies between 19 and 26 mm after the first winter, between 40 and 52 mm after the second winter, and between 53 and 56 mm after the third. The largest tadpole had a body length of 68 mm and a total length of 162 mm. Growth occurs mostly in June, July, and August and it varies with temperature. Metamorphosis never occurs before a tadpole reaches a body length of 43 mm, a total length of 100 mm, and has posterior legs of 50 mm in length. This usually happens in July or at the beginning of August. The tadpoles that are about to undergo meta...