Most of the time these two species are easily distinguishable by their colour - Leopard Frogs are usually green and Pickerel Frogs are usually brown. But, be on your guard, there are a few brown Leopard Frogs and green Pickerel Frogs out there. Here are a few clues for telling them apart. First, check the spots between the lateral folds - those two long ridges that run along a frog's back from the eye to the hind legs. Spots on the Leopard frog are oval here and will be bordered with pale green even if the rest of the frog is brownish. Spots on the Pickerel Frog are rectangular and sometimes adjacent spots blend together. Second, if you get a chance to see the underside of the frog, the groin area in Pickerel frogs will be tangerine orange in colour.