LEOPARD FROG

Rana pipiens

AMPHIBIAN

Order Anura

Description

About 4 in long, female slightly larger than male; smooth skin is green with white-edged, dark, irregularly shaped blotches on its back. White underparts; a light-colored ridge of skin runs down each side of the back. Males have paired vocal sacs, each sac located just above the shoulder, and a pad on the inner side of each thumb for grasping traction.

Range

This species is the most wide-ranging amphibian in North America, from southern Canada south through most of the U.S. Currently, it is absent without explanation from eastern Canada.

Photo © James P. Rowan Photography

Ecology

Habitat

marshes, bogs, backwaters and ponds, moist meadows and grassy woodlands. Even though it ventures away from ponds during summer, it must continue to live in moist conditions or it will dry out. Amphibians have a thin, permeable skin, and evaporation of water through this thin skin is so rapid that the frog must continually replace those fluids by soaking itself. Frogs do breathe with lungs, but they also get oxygen from the moisture that covers them, and so "breathe" with their skin.

 

Niche

carnivorous: principal food is insects, but also eats spiders and various other invertebrates. Tadpoles live on algae and diatoms. Newts eat frog eggs, fish and insect larvae eat tadpoles, garter and water snakes feed on adult frogs. Small mammals that frequent these habitats also dine on whatever R. pipiens stages they can catch. Mostly nocturnal, but will also be active during the day. Mostly aquatic, in habit, but feed primarily on terrestrial prey. Winter is spent in bottom mud or under a submerged log or rock.

Life History

Mating usually occurs in April, with males vocalizing. Breeding male seizes any frog, but retains hold only if the one seized is plump and silent. Females probably cannot croak because of internal pressure of the egg mass. Egg mass is a flat sphere 3-6 in across, attached to submerged vegetation or resting on pond bottom. Tadpoles hatch in a few days and metamorphose into 1 inch-long froglets in 2-3 months, depending upon climate conditions. Sexual maturity reached about 3 yrs. Life span in captivity up to 9 yrs.

Special Adaptations

• Patchy blotches on frog's back blend with irregular pattern of sun-dappled water plants, helping to camouflage it.
• Powerful hind legs allow frog to cover 36 in in one jump.
• Zig zag jumping pattern helps to confuse predators.
• Frog will jump toward water, attracted by the light reflected off the water's surface; it will continue zig zag jumping under water and surface amid plants that conceal it while predator keeps searching area of original dive.
• Eyes located on top of head provide frog with ability to see behind and above itself.