The Vanishing Frog

Anatomy of a Frog
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FROG LEGS

There are ground-dwelling frogs, aquatic frogs (those that live in water), arboreal frogs (those that live in trees) and burrowing frogs, and the structure of their legs and feet vary greatly. Burrowing frogs can't hop like other frogs, but instead have short, muscular hind legs that they use primarly for digging. They also have a special hardened plate on each foot, called a metatarsal tubercle, that they use like a shovel to dig through soil.

Arboreal frogs have sticky pads on the tips of their fingers and toes that help them grip tree trunks and branches. The surface of the pad consists of interlocking cells. When the frog applies pressure to a surface, the interlocking cells grip small irregularities. The pressure drains away all but a thin layer of moisture between the pads; the remaining moisture helps the frog "stick" to the tree through capillary action (when water clings to a surface). These frogs have special hip joints that allow them to walk instead of hop (which can be dangerous).

Some tree-dwelling frogs have specialized webbing between their toes that they use to glide between the tree tops. Aquatic frogs have webbing too, which allows them to swim efficiently with help from their strong hind legs.

The legs of ground-dwelling frogs are designed for jumping. In fact, frogs are the most exceptional jumpers of all vertebrates, many species can leap 20 times their own body length or more. Here's where the power comes from: three core bones of the hind leg are fused into a single, strong bone; the limbs are elongated, allowing the frog to apply force to the ground longer; and almost all the leg muscles contribute to the act of jumping. Only a few small muscles bring the frog's legs back to resting position, and a few others maintain posture.

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Anatomy of a Frog

	FROG EYES The frog's eyes help it catch insects, avoid predators and swallow.		FROG EARS The frog hears sound through its ear drums ... and its lungs!		FROG MOUTH The frog has a sticky tongue for catching insects. It even has teeth!
	FROG LEGS Jumping is as important to some as clinging and burrowing is to others.		FROG SKIN Skin allows for the transfer of moisture and protection from predators.		THE VANISHING FROG Go back to The Vanishing Frog main page for more frog facts and frog fun.