Common Reptile and Amphibian Species of Northwestern Ontario





Rana septentrionalis
Mink Frog


Distinguishing Features - Medium-sized frog. Overall colouration, green with black spots or mottling (the dark pigment is sometimes very invasive); green may only be seen on the head and lips. Generally, the dark pigment forms a network or reticulated pattern on the back. Underside, white or yellowish with or without gray markings. Back ridges may be present, reduced, or absent. The tympanum (circular eardrums) of males is larger than the eye; those of females are the same size or slightly smaller than the eye. Eyes, positioned slightly on top of head. Feet, fully-webbed.

Mink Frog Size -
up to 7.6 cm (3 in)


Found throughout the southern regions of Northwestern Ontario in and around permanent wetlands like lakes, ponds, deeper bogs, and slower portions of rivers. In more open areas, they stay very close to these waters, but they may move a short distance if the wetland is surrounded by damp, heavy forest with numerous bogs.


Mink frogs breed from late May into August. Females lay masses of eggs that number 3,000 or 4,000. Tadpoles metamorphose in about three months, and some not until their second year.


Mink frogs eat aquatic or flying insects, earthworms and other invertebrates.

Males vocalize while floating with a knock, knock, knock call. Mink frogs are the most aquatic of Northwestern Ontario frogs, rarely leaving the water except for long periods of high humidity or during heavy rains. They generally remain in the wetland environment, away from shore sitting on lily pads or heavy carpets of aquatic vegetation.

In the winter months, they hibernate underwater in their home lake, pond, or river.

Mink frogs have a minklike or rotten onion smell, hence the name.

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