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Canadian Herpetological Society





Société d'herpétologie du Canada



Lithobates septentrionalis

formerly Rana septentrionalis

Mink Frog / Grenouille du Nord


Mink Frog

Description
The Mink Frog is a moderate sized frog, olive to brown in colour and may have dark spots or mottling on the sides and hind legs. The belly is yellowish and the dorsolateral ridges may be prominent, partial or absent. It has a large tympanum and slightly upturned eyes. The name Mink Frog refers to its pungent, musky odour. The webbing on the hind foot reaches the last joint of the longest toe. Adults may reach 7 cm.

Call
The Mink Frog call consists of a rapid series of three or more croaks like the tapping of a metal hammer on wood. It is easily confused with that of the Northern Green Frog but lacks the twangy bounce of that call. A large chorus sounds like popcorn popping.

Confusing Species
The Northern Green Frog is similar although it can get larger and always has partial dorsolateral ridges. In addition, the Northern Green Frog has a white belly.

Distribution
The Mink Frog is a northern species which has most of its distribution in Canada. It is found in southern Manitoba, and through much of Ontario, Quebec, New Brunswick, Nova Scotia and Labrador. It is also found in some states in the Great Lakes basin.

Habitat
The Mink Frog is highly aquatic and rarely found on land. It prefers large, cold, permanent ponds, lakes and slow moving rivers with abundant vegetation.

Reproduction
Breeding occurs from late spring through mid summer. Choruses increase in intensity through the night and peak before dawn. Egg masses are globular but have never been observed in the wild. Tadpoles overwinter in water before transforming.

Natural History
Mink Frogs are very aquatic but may be seen on land in late fall. They are more skittish than Northern Green Frogs and Bullfrogs. Adults hibernate under water.

Conservation Concerns
The Mink Frog is one of the few species of amphibians with most of its distribution in Canada. Populations are apparently stable.