Basic Frog Facts

Adaptations Frogs are part of the amphibian order, Anura. Frogs have four legs, no neck, and no tails as adults. Frogs have loose, mucous lined skin to help them escape from predators. Frogs live "dual lives"--part in the water, part on land. Frogs breathe through gills only as tadpoles. Frogs breathe though underdeveloped lungs as adults.

Adaptations Adult frogs also breathe through their skin, called "cutaneous respiration," which limits body size. The mucous lining helps keep frogs hydrated, and is required for cutaneous respiration. The backs of frogs are dark, while their undersides are light, in order to protect them through camouflage on land and water, respectively.

Adaptations Frogs live on land as adults, but must live near a major water source to help keep their skin moist, for reproduction, and for certain stages of life. Frog brains are smaller and less developed than other vertebrates. Strong muscles and special fused bones help frogs be powerful swimmers and jumpers

Fish vs. Frogs Fish have scales; frog skin is smooth & mucousy. Fish have a single loop circulatory system with a two chambered heart frogs have a double loop circulatory system with a three chambered heart. In fish, deoxygenated and oxygenated blood is completely mixed, while in frogs it is only partially mixed. Both are cold blooded (ectothermic). Fish breathe through gills as adults, frogs do not. Fish can only swim, and require constant water habitats.

Snakes vs. Frogs Snakes don’t have limbs; frogs have 4 legs. Frog eggs are shell-less & fertilized externally in water. Snake eggs have leathery shells, are laid on land, and are fertilized internally. Snake hearts have a partially divided ventricle, therefore have less mixing of blood than frogs. Snakes have scales; frog skin is smooth. Both swallow their prey whole.

Mammals/Birds vs. Frogs Frogs have larger olfactory lobes than birds. The cerebrum of frogs is less developed than that in mammals. Mammals have hearts with four chambers (prevents oxygenated and deoxygenate blood from mixing), frogs only have three chambers (allows some mixing of blood).