The frog is an amphibian in the order Anura (meaning "tail-less" from
Greek an-, without + oura, tail), containing 5,250 species in 33
families.
The use of the term "frog" in common names usually refers to species
that are aquatic or semi-aquatic with smooth or moist skins, and the
term "toad" generally refers to species that tend to be terrestrial
with dry, warty skin.
The biggest kind of frog is the Goliath frog (Conraua goliath), coming
from Cameroon in West Africa: its body can reach the size of nearly a
foot long and it can weigh as much as a large housecat.
The smallest frog is the Gold Frog (Brazilian Psyllophryne Didactyla),
it measures only 9.8 millimetres in body length (with legs drawn
in).
