The Northern Leopard Frog (Rana pipiens) is one of many species that frequents New York’s grassland areas near ponds and marshes and can easily hide itself in the tall grasses during the summer months.
Northern leopard frogs are so named for the array of irregularly shaped dark spots that adorn their backs and legs. They are greenish-brown in color with a pearly white underside, light-colored ridges on either side of their backs, and a white stripe on their upper lip. They are considered medium-sized frogs, reaching lengths of 3 to 5 inches, nose to rump. The Northern Leopard Frog’s rounded spots with light borders help to differentiate it from the Pickerel frog, which has square spots and bright orange or yellow on the inner part of their hind legs.
The Northern Leopard Frog is found throughout northern North America, except on the Pacific Coast. They generally live near ponds and marshes, but will often venture into well-covered grasslands as well, earning them their other common name, the meadow frog.
Northern leopard frog tadpoles and froglets are herbivores, feeding mostly on algae and other aquatic plants, which they scrape off submerged rocks and twigs with a rasping mouth. They grow rapidly and by late spring are about 1 inch long and begin to develop legs. These tadpoles metamorphose into frogs, and by early summer the small frogs leave the water to begin their life on land.
Not only can adult frogs can live out of water, but they can breathe through lungs as well (although they also obtain oxygen through their moist, thin skin). Furthermore, unlike tadpoles and froglets, adult Leopard frogs will eat just about anything they can fit in their mouths. They are known to eat beetles, ants, flies, worms, smaller frogs (including their own species), birds, and garter snakes.
During the winter Leopard frogs hibernate on the bottom of ponds. When winter ends, Northern leopard frogs are one of the first amphibians to emerge from hibernation in the spring and they are the first prolonged breeder to start calling.
The Northern leopard frog is often difficult to hear because it does not call in large groups’ as do other frog species. Individual leopard frogs call from the edge of the water. The Northern leopard frog has a distinct mating call. The call is a deep rattling snore interspersed with clucking grunts that may be single or multiple syllables. The leopard frog call can also be described as the sound a finger rubbing against a balloon.
The habitat of the adult frog is the narrow zone between water and grassland. Furthermore, Northern leopard frogs have innumerable predators. Fish, large salamanders, snakes, raccoons, mink, skunks, bullfrogs, herons, and hawks all prey upon frogs. One adaptation that frogs like the Northern Leopard Frog have developed to avoid predation are powerful legs for swimming and jumping. Leopard frogs can leap an astonishing 5 to 6 feet in a zigzag pattern to avoid predators.