Rana septentrionalis BairdThe family Ranidae of typical frogs consists of 45 genera and 586 species and is distributed nearly worldwide.
The genus Rana is represented in the Maritimes by 6 species in New Brunswick and Nova Scotia, while 3 occur on Prince Edward Island.
The toes on the front legs are unwebbed.
Breeding males can be told from females by the swollen base of the thumbs on the forelegs. This is related to the tight holding they do during amplexus.
There are regional colour variations. In about half the population at Uniacke Lake, Hants County, the back is green, bronze and black. Black dominates the pattern on many of them. One individual had a green head, black back and a large bronze blotch on each side.
Size: body length of 43 newly transformed young ranged from 2.8 to 4.2 cm. Adult males, 17 measured, from 4.9 to 6.8 cm. Adult females, 12 measured, 5.4 to 7.0 cm.
The dorsolateral fold may be absent or may extend up to two-thirds the length of the trunk. The folds are less prominent than on Green Frogs.
Distribution in Canada: Nova Scotia and New Brunswick north to Anticosti Island and southern Labrador, west to south-eastern Manitoba. In the United States, south into northwest Maine and New York, and west to northwestern Minnesota.
In Nova Scotia, Mink Frogs have been found in scattered localities throughout most of the mainland and Cape Breton Island.
Earliest spring record is May 7, 1968, a juvenile male at Kejimkujik Lake in Queens County.
Latest fall record is September 30, 1924, at Cheticamp Lake in Victoria County.