" " This gray tree frog has evolved with some pretty handy camouflage. Wirestock Creators / ShutterstockThe green tree frog is a common frog in the central to southeastern United States, often found near ponds with plentiful vegetation. Males are usually smaller and use advertisement calls during breeding season to attract female frogs. Male green tree frogs are especially known for their loud, croaking calls. AdvertisementThe gray tree frog, also known as Hyla versicolor, can change color between gray, green, and brown, depending on its surroundings.