Technically, a toad is a kind of frog. Even so, the two look different. A frog's skin is usually smooth and slimy. A toad's skin is bumpy, a bit like warts, and toads have short legs made for short hops and crawling.

Wood frogs spend the winter frozen and thaw out when the weather warms. A frozen wood frog thaws from the inside outward.

Frogs and toads call out loudly when it is time to find a mate. They make their calls with the help of one or two pouches of skin called vocal sacs. A male bullfrog's low call can be heard for more than a kilometer. Some frog calls are so loud they can be heard up to a mile away.

Most frogs and toads start life in the water. A tadpole is a young frog that lives in water and breathes with gills. The change from a tadpole into a frog is called metamorphosis. A bullfrog tadpole can take two winters, or almost three years, to turn into a frog. Baby Surinam toads are different. They grow up on their mother's back and do not swim around as tadpoles.

Toads have large glands behind the eyes, called parotoid glands, that make their poison. The poison from toad glands is called bufotoxin. It can kill small animals and cause allergic reactions in people. It is best not to handle a toad, and nobody should lick or eat one.

Poison dart frogs have bright colors that warn predators they are poisonous. In the wild, they have poison in their skin, which makes them too toxic to touch.

Frogs and toads live almost everywhere on Earth except Antarctica. In 1935, people brought cane toads to Australia to kill sugarcane beetles.

Most frogs and toads eat insects. They eat so many that they help keep a large part of the world's insect numbers down.

Words to know

• tadpole: young frog
• metamorphosis: body change
• glands: body parts
• bufotoxin: toad poison
• thaws: warms up