Reports have stated that Mink frog populations are declining, but they are not in serious trouble yet. The decline might be due to competition from the green frog, a larger, ubiquitous species (Harding 1997).
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Development - Life Cycle: metamorphosis
Mink frogs have a largely aquatic diet. They feed mainly on spiders, snails, dragonflies, whirligig, and beetles, all of which can be found on the surface of the water or on lily pads. Mink frog tadpoles feed mainly on algae (Harding 1997).
The Mink frog is found in Minnesota, Wisconsin, northern Michigan, and in northern New York. They are also found in Canada ranging from Quebec to the southeastern portions of Manitoba (Mossman et al 1999).
Biogeographic Regions: nearctic (Native )
They enjoy permanent wetlands since they are primarily aquatic creatures, but they will move on the land if the conditions are damp and covered in heavy forest (Reptiles & Amphibians of Minnesota 1999).
Aquatic Biomes: lakes and ponds; rivers and streams
Range lifespan
Status: wild: 6 (high) years.
Adult length: 4.8 to 7.6 cm
Their backs are green, olive, or brown with irregular blotches. The dorsolateral folds are poorly developed or sometimes even absent in this species. Webbing extends to its fifth digit on its hind feet. Their undersides are whitish or yellowish. They have round spots or stripes on the upper parts of their hind legs. There is some sexual dimorphism. Male Mink frogs have larger tympanums than females. Males also often have a bright yellow throat compared to the white or pale yellow throat of the female. The tadpoles prior to metamorphosis have a dorsal coloration that is green, olive, or brown with scattered spots. Tadpoles also have a yellowish underside with a long pointy tail (Harding 1997).
Other Physical Features: ectothermic ; bilateral symmetry
Mink frogs do not begin to breed until late May and usually end in August. Males vocalize while floating on the water (Reptiles & Amphibians of Minnesota 1999). In the Great Lakes area the eggs are deposited in June and July. An average female will lay between 500 and 4,000 eggs in one cluster. The cluster may be laid up to a meter under the water and will eventually sink to the bottom before hatching. The tadpoles are in the larvae stage for about a year before metamorphosing into froglets. It takes the female about two years to become sexually mature whereas it takes the males only about a year to become mature (Harding 1997).
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate)
Average age at sexual or reproductive maturity (male)
Sex: male: 547 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 730 days.
The mink frog (Lithobates septentrionalis) is a small species of frog native to the United States and Canada. They are so named for their scent, which reportedly smells like a mink. The scent is more akin to that of rotting onions to those unfamiliar with mink. It is also sometimes referred to as the north frog.
The mink frog is a small frog, growing up to 4.8 to 7.6 cm (1.9 to 3.0 in). The dorsum is generally green in color, with darker green and brown blotching and the belly is a cream, yellow, or white. They are sexually dimorphic in that males typically have a bright yellow colored throat, while females have a white colored throat, and the tympanum of the male is larger than the eye, while the female's is smaller than or the same size as the eye. The frogs have a pale-colored underside and bright green lips.
The mink frog is predominantly aquatic, living among the vegetation (especially among lily pads) in ponds, swamps, and streams around wooded areas. They feed on a wide variety of things, including spiders, snails, beetles, and other invertebrates. As tadpoles they consume primarily algae and decaying plant matter.
Mating generally takes place in late spring and early summer. These frogs prefer cold, well-oxygenated wetland breeding sites where during the late night hours, but occasionally during the day, males call to attract females while floating on the water's surface or partially resting on floating vegetation.[2] Between 500 and 4000 eggs can be laid by the female at any one time, generally in deep water. Egg masses are usually found close to floating vegetation and hatch within days of being deposited.[2] Tadpoles remain in the larval stage for approximately one year before metamorphosing into froglets. Maturity is reached in a year for males, and two years for females.
Mink frogs are found in the United States in the states of Minnesota, New Hampshire, Wisconsin, Michigan, Maine, Vermont, and New York. They are also found in Canada in the provinces of Nova Scotia, New Brunswick, Newfoundland and Labrador, Quebec, Ontario, and Manitoba. This largely aquatic frog's southern range limit is at the highest latitude of any North American frog and there is evidence that more southern populations of this frog became extinct within the past century.[2]
In recent years, it seems that the general populations of mink frogs are in decline.[3] In a 1999 study conducted by David Gardiner and David Hoppe it was noted that there was an increase in mink frog deformities. "The spectrum of deformities includes missing limbs, truncated limbs, extra limbs (including extra pelvic girdles), and skin webbings. We also describe a newly recognized malformation of the proximal-distal limb axis, a bony triangle. In this abnormality, the proximal and distal ends of the bone are adjacent to one another forming the base of a triangle. The shaft of the bone is bent double and protrudes laterally, the midpoint of the bone forming the apex of the triangle."[4] The study comes to the conclusion that these deformities are a result of exposure to exogenous retinoids, but more study is needed to make a sure determination.
The mink frog (Lithobates septentrionalis) is a small species of frog native to the United States and Canada. They are so named for their scent, which reportedly smells like a mink. The scent is more akin to that of rotting onions to those unfamiliar with mink. It is also sometimes referred to as the north frog.