Description
Mink frogs are green to olive-gray, with dark spots or mottling on the back. Sometimes there is a ridge along each side of the back but usually it is absent. The webbing between the hind toes extends to the last joint of the 4th toe and to the tip of the 5th toe. Dark marks on the upper side of the hind legs form irregular blotches that are elongated along the long axis of each leg. These frogs have odorous skin that smells like a mink or crushed scallions. Maximum size is around 3 inches (7.6 cm) snout-vent length. The breeding call is a rapid, sharp "cut-cut-cut-ghrrr" or "tok-tok-tok-tok-tok;" a chorus may sound like distant hamemring or horse's hooves on a cobblestone road. Larvae are greenish or brown with dark spots or mottling that may extend onto the tail; the belly is yellowish and opaque; the tail tip is long and sharply pointed (if not damaged); maximum total length is about 4 inches (10 cm). Egg masses are globular, about 3-6 inches in diameter, and contain several hundred eggs.
Habitat
Mink frogs inhabit cold lakes and ponds and their shallow peripheral pools, and inlets and outlets of ponds and lakes, often among emergent or floating vegetation (e.g., lily pads) in open water or along shores. They are highly aquatic but sometimes venture away from water onto land during very wet weather. Hibernation sites are underwater. Eggs and larvae develop in permanent lakes and ponds. Eggs are attached to submerged vegetation but may later sink to the bottom.
Ecology
The strong odor of mink frogs may serve as an anti-predator mechanism, but these frogs are nevertheless eaten by great blue herons, raccoon, and other animals.
Reproduction
Breeding occurs in late spring and summer, mainly late May to early August (peak often June-July). Adult females deposit clutches of a few thousand eggs, June to August. The aquatic larval stage lasts 1-2 years. Individuals become sexually mature 1-2 years after metamorphosis.