4 Extreme Amphibians-Low

Extreme Amphibians FOCUS Question What makes some amphibians unusual?

What Are Amphibians? Have you ever been to a pond? Did you see a frog A frog is one kind of amphibian (am-FIH-bee-in). Amphibians lay eggs in water. When the eggs hatch, the young may not look like their parents. Many amphibians start off as tadpoles. The tadpoles live in water and have gills. Adult amphibians have lungs and can live in water or on land. You may know a lot about frogs. But did you know that some amphibians are see-through? Some have no legs or no eyes. Some can even freeze in the winter! These are extreme amphibians!

Big and Small Frogs The most common amphibians are frogs. Frogs are usually small enough to fit in your hand. One frog is much smaller. It is only the size of a fly! It is the world's smallest vertebrate. It lives in the rainforests of New Guinea. It is so small that scientists didn't discover it until 2009. Other frogs can be enormous. The Goliath frog is longer than your forearm. It can weigh over 3 kilograms (7 lb.). It is big enough to eat mice! This huge frog lives in tropical forests of western Africa.

Hot and Cold Frogs Some frogs live in deserts. The water- holding frog lives in parts of Australia that are dry for most of the year. When it finally rains, the frog soaks up water. The outer layer of its skin gets loose and fills up like a water balloon. The frog digs a burrow and can live off this water for months. What do frogs do in winter, when water freezes solid? Some frogs freeze up! Alaskan wood frogs become almost solid during winter. They have special blood that can freeze without hurting their body. When spring comes, they thaw out and hop away.

Poisonous Frogs Many animals eat frogs. Some frogs fight back, but not with teeth or claws. They have poisonous skin. A single poison dart frog could kill ten people. Luckily, these frogs are easy to spot. They are candy colored. They can be blue, red, green, orange, or yellow. The bright color warns predators that might try to eat them, It says, "Stay away!" Do You Know? Poison dart frogs get their poison from their diet. They eat ants They use chemicals from the ants sting to make their own poison. If they don't eat ants the frogs are not poisonous.

Strange Salamanders Salamanders and newts are shaped like lizards. Like all amphibians, they lay eggs in water. The young live in the water and breathe through gills. Some adult salamanders live on land. They have lungs and breathe air Others stay in the water their entire lives. The largest amphibian on Earth is a salamander. The Chinese giant salamander can weigh 50 kilograms (110 lb.). It can grow to be 1.4 meters (4.7 ft.) long. This salamander lives in cold mountain streams, where it hunts fish. It stays in the water its entire life. Math Moment How many Goliath frogs would it take to weigh more than one Chinese giant salamander?