Frogs Research Guide
Agalychnis callidryas (Red-Eyed Treefrog)
Red-eyed treefrogs live in tropical rainforest areas of Central America, south to Colombia. They use their broad “suction cup” toes to climb trees and attach to the underside of leaves. Their red eyes might be an adaptation that allows them to see at night, which is when they are active, or they may use them to startle predators. They lay eggs on the underside on leaves hanging over water so that the tadpoles fall into the water after hatching. If unhatched tadpoles are threatened by predators they will quickly hatch and escape (see video).
Breviceps mossambicus (Mozambique Rain Frog)
The Mozambique Rain Frog, also known as the Flat-Faced Frog, lives in central and southern Africa. Its natural habitats are savannah, bushy country and open woodland, especially the moister parts of these. It has bulging eyes, a stout body, and short limbs. In dry weather the Mozambique Rain Frog conceals itself under rocks or in hidden places among tree roots where it can conserve some moisture.
Ceratophrys cranwelli (Cranwell’s Horned Frog or "Pacman" Frog)
Cranwell's Horned Frog is a terrestrial frog native to the dry Gran Chaco region of Argentina, Bolivia, Paraguay and Brazil. They are often called Pacman Frogs because of their resemblance to the popular video game character. The Pacman Frog’s dark color scheme aids in camouflaging it as it burrows and waits for its prey. Though generally inactive, they are aggressive eaters, and are capable of leaping for several body lengths in order to capture prey. At extreme temperatures, these frogs enter a period of estivation, developing a thick layer of protective skin to trap moisture and aid in respiration. When estivation is complete, the frog uses its front and hind legs to help shed the protective layer. In many cases, the frog uses its jaws to help pull the skin over its back, often eating the skin in the process.
Eleutherodactylus coqui (Common Coquí)
The Common Coquí is native to Puerto Rico, where they are a beloved national symbol. Coquí frogs are nocturnal and are known for their loud call that sounds like “koh-kee”. They spend most of their time in trees. Coquí frogs have no tadpole stage; adults mate and the female lays eggs in small nooks on trees or among leaves. The male protects the eggs and keeps them moist. Male Coquí frogs may guard more than one clutch of eggs at a time. Because the eggs can go unnoticed, Coquís have invaded Hawaii via the nursery trade and now live on four Hawaiian islands. In contrast to Puerto Rico, Coquí frogs are viewed as a nuisance in Hawaii.
Hemisus guttatus (Spotted Shovelnose Frog or Spotted Snout-Burrower)
The Spotted Shovelnose Frog can be found in the arid savannah of South Africa. It has a rounded body with a small pointed head and pointed snout, and tiny eyes. Its skin is dark purple or brown, with numerous yellow dots on the back. The hard, flattened snout is used for burrowing head-first, as the common name of Spotted Snout-Burrower suggests. The snout is pushed into the ground with up-and-down movements, like a spade, while the hands and mole-like claws dig into the soil and the back legs exert force. This frog is unusual in its head-first burrowing, as most burrowing frogs do so feet-first. During the dry season, Hemisus guttatus estivates within muddy hollows and banks. The first rains of the season signal the frogs to breed. Each heel bears a small, keratinized ridge on the inner surface, facilitating burrowing. These frogs spend most of their time underground in areas of flat, sandy soil that tend to flood during the rains.
Lepidobatrachus laevis (Budgett’s Frog)
Budgett’s frog lives in Paraguay, Bolivia and Argentina, in both semi-arid and moister areas. It has a flattened body and large head with wide jaws. During dry times it will remain inactive underground in a cocoon of dead skin, which helps it retain moisture. These frogs hunt at night, ambushing prey when it passes by. Females lay large numbers of eggs in temporary pools of water where they develop quickly into tadpoles.
Polypedates leucomystax (Common Treefrog)
Known under numerous common names including Four-lined Treefrog, Golden Treefrog or Striped Treefrog, the Common Treefrog is a small to medium-sized frog that lives in sub-tropical and tropical areas of Southeast Asia. The hind feet are webbed while the front feet have wide cushioned toes that can grip onto vegetation. Females deposit from 100-400 eggs in oval-shaped foam nests constructed on plants above temporary pools, or attached to a surface by the water's edge. Hatching takes place after three to four days, when the larvae wriggle free of the foam nest and drop into the water below.
Rana berlandieri (Rio Grande Leopard frog)
Rio Grande Leopard Frogs live in central Texas to southeast New Mexico, most commonly in streams that run during all or part of the year. They avoid predation by hunting at night, hiding under vegetation and rocks, and by benefiting from their cryptic (camouflaging) coloration. They may hibernate in cold areas but are generally active throughout the year. Eggs are laid in water and tadpoles develop with no parental care.
Rana spinosa or Quasipaa spinosa (Giant Spiny Frog)
Rana spinosa is known under many common names, including Chinese Spiny Frog, and Chinese Edible Frog, because it is considered a delicacy in some parts of the world. This frog is dark brown with dense, yellowish mottling, helping it camouflage in its environment. It can be found in rocky streams and other wet areas in China, including Hong Kong. Males have distinctive keratinized skin spines on their chests. The legs are sturdy and muscular, and the toes are entirely webbed. Because it is harvested for food, populations are declining.
Xenopus laevis (African Clawed Frog)
The African Clawed Frog is well known because it has been used as a laboratory animal and kept as a pet. Although they are native to southern Africa, they have been introduced to many areas of the world. This frog has a flattened body and wedge-shaped head, and webbed feet which are suitable for its aquatic lifestyle. They can be found in streams and warm, stagnant ponds in arid and semi-arid regions. They are hardy and long-lived, some captive individuals living for more than 20 years.
Links to more information
General information on frogs and amphibians as well as detailed information on many individual species: