Next to the green frog, the pickerel frog is the most abundant frog in New England. It is often confused with the northern leopard frog, which it closely resembles. The spots on a pickerel frog’s back are squarish and aligned in rows, whereas the leopard frog’s spots are rounded, and randomly scattered over its back. In addition, the male pickerel frog has bright orange on the inner surface of its hind legs, which the leopard frog lacks. The pickerel frog is very sensitive to pollution, so its presence is indicative of good water quality.