Frogs

A perfect day in the life of a frog is one with warm weather, a pond and lots of bugs. The more bugs the better. A frog's diet consists almost entirely of insects, which they catch with their long, sticky tongues. But bugs are an acquired taste enjoyed only by adult frogs. Frogs have four distinct, and very different, phases in their lives: Life one: The Egg. Frogs start out as eggs, floating in a pond or marsh. When they hatch what comes out? Not frogs, but... Life two: Tadpoles. Tadpoles have gills like fish and are very nearly fish. They are herbivorous, eating algae and diatoms by filter feeding. But as they mature the most amazing thing happens: everything changes, Life three: Metamorphosis. The tadpoles grow four legs and their tail falls off, they grow lungs and their eyes move. They look different, they move differently, they breathe differently and they eat differently. They go from being a prey to a predator! Life four: The Frog. As adult frogs they cannot use their gills to breath underwater anymore, but they don't breath entirely with their lungs like you and I do either. Actually, they get a lot of their oxygen through their skin! They have an aqueous film on their skin that allows oxygen to dissolve, and then is easily passed through their skin, which is very permeable (stuff can pass through easily, like a sponge). Thats how they can stay under water for long periods of time. Their skin also allows water to enter their bodies, so they have little need to drink. You can tell where a frog lives by looking at it. If it is brown and lumpy and has regular feet, it probably lives mostly on the ground, where the brown would camouflage it. If it is smooth and has webbed feet, it probably lives mostly in the water. Tree frogs are the color of leaves. But some green frogs spend time in the water too, in algae. More frog facts: Frogs were some of the first creatures to make noises. They croak to attract a mate, but some can also whistle, burp and click. Frogs hibernate during winter, but also can hibernate during a drought when there is no water in their pond. Big frogs have been known to eat little frogs. RISK: Because frogs need water and their skin is permeable, they are very vulnerable to any toxins in the water. Some frog populations are endangered or already lost because of toxins in the environment and loss of habitat. Decimated frog populations in an area can be an early warning sign that the area has become toxic or polluted.