The World of Amphibians
There are about 4,780 species of amphibians known to naturalists, and there may be 300 to 500 more that have yet to be discovered. In the United States and Canada there are only 250 species. The world’s amphibians, most of which live in tropical areas, fall into three major groups (called orders) with special characteristics.
Frogs of all kinds (including toads) make up the biggest order of amphibians, with about 4,000 species around the globe. North America north of Mexico has 100 frog species. There are many kinds of frogs, including treefrogs, true toads, spadefoot toads, and many others.
All About Frogs
Frogs have large eyes on the tops of their heads. Many frogs have poison glands in their skin. Most frogs and toads have distinct songs or calls that are used by males during the mating season. They produce these calls by inflating a pouch in the neck, called the vocal sac. Frogs have short front legs and long, powerful hind legs. They have four toes on their front feet and five toes on their hind feet. Many frogs have a hump in the middle of their backs, where the pelvis connects the backbone to the hind legs.
Salamanders are not nearly as common as frogs, totaling only some 410 known species. North America, with about 150 species, is the best place in the world to see salamanders.
What Makes a Bird a Bird? Feathers!
Birds are the only creatures with feathers. ”Light as a feather” is no exaggeration. Feathers weigh very little, but birds could not live without them. Feathers allow flight, provide terrific insulation, and keep rain and snow away from the skin. They can be colorful as a rainbow or make a bird blend in perfectly with its surroundings.
Birds have several different types of feathers, including contour feathers and down feathers. Soft and fluffy, down feathers grow under the body feathers and provide insulation. A contour feather may be a large, stiff feather on the wing or tail...