DEEP: Northern Leopard Frog

Northern Leopard Frog

(Rana pipiens)

{Northern Leopard Frog}

IDENTIFICATION: A medium-size frog often confused with the pickerel frog from which it is distinguished by a dorsal pattern of dark circles with white edges irregularly distributed over a green or brown dorsum. The belly, thighs, and groin are white. When disturbed it tends to flee in a series of zigzag jumps into high grass. Adults 50-70 mm body length.

This species is restricted to seasonal wet meadows and forests located on the floodplain of a river or large stream. Leopard frogs are locally common along sections of the Connecticut River and its tributaries, the Farmington, Scantic, and Coginchaug Rivers. Populations are scattered in Litchfield County and at a few other sites west of the Connecticut River. This species is often confused with the widespread pickerel frog. Leopard frogs in Connecticut represent two distinct gene pools. Klemens (1993) reporting on biochemical and morphological studies conducted on Connecticut leopard frogs found that animals from the Connecticut River drainage are referable to the northern leopard frog. Those from the Housatonic drainage of western Connecticut have some of the distinctive genetic and morphological markers of the southern leopard frog, Rana sphenocephala utricularius. One major distinction is that the males of the Connecticut River population possess vestigial oviducts, a characteristic of the northern leopard frog, while males from the Housatonic drainage lack vestigial oviducts. These data point to two separate origins of Connecticut's leopard frog population.

Leopard frogs have disappeared from some areas of Connecticut; historical data and reports indicate that they were once more widespread. They are intolerant of acidic conditions, which may account for their present distribution in the state to limestone areas or areas of circum-neutral soils. Loss of floodplain habitats through impoundments, levees, and channelizing has eliminated habitats upon which these frogs depend. The leopard frog is considered a "Special Concern" species within Connecticut and collection is prohibited under Section 26-66-13-A of the Connecticut Code.

Frogs | Amphibians and Reptiles in Connecticut