Frogs are amphibians that are known for their jumping abilities, croaking sounds, bulging eyes and slimy skin. They live all over the world and are among the most diverse animals in the world, with more than 6,000 species.
Frogs substantially outnumber the two other groups of amphibians — salamanders and caecilians. According to the American Museum of Natural History (AMNH) online reference site, Amphibian Species of the World, which is updated in real time, as of late April 2015, there are 6,482 species in the Anura order (frogs and toads), 691 species in the Caudata order (salamanders and newts) and 204 species in the Gymnophiona order (caecilians). Caecilians look like large worms or slick snakes, according to the San Diego Zoo. They have no arms or legs, and live underground in a network of tunnels.
There is no scientific distinction between frogs and toads, according to the University of Michigan Museum of Zoology. Frog and toads both belong to the Anura order, but are found in different families. "True toads" make up the Bufonidae family, which includes 580 species.
Frogs and toads do have specific traits that define them, however, according to the Maryland Zoo. For example, frogs are mostly aquatic; most toads live on land (but near water). Frogs have teeth; toads do not. Toads of both sexes have a rudimentary ovary called a bidder's organ. Frogs are also typically longer than toads.
Also, frogs have smooth, slimy skin; toads have dry, bumpy skin. The bumps, however, are not warts, and a person cannot get warts from handling a toad, according to the San Diego Zoo. However, toads have glands behind their eyes that can secrete a burning milky toxin.