Frogs and the similar toads are a large family of hundreds of species of batrachian amphibians, with a nearly worldwide distribution, absent only from high latitudes and remote oceanic islands. Even in deserts, species such as the water-holding frog, which is used as a drinking bottle by Australian Aborigines, are to be found, buried deep below the ground between the infrequent rains.
Frogs in Science
Frogs have often been the subject of scientific experiment, whether in high school science class dissections or Voltaire's 1766 experiments, in which he discovered that frogs hear with their legs. The discovery that a frog's leg will kick if an electrical shock is applied to it was the scientific basis behind the reflex tests now common in doctors' offices.
Frogs in the Bible
The second of the Ten Egyptian plagues was of frogs. In Egyptian culture, frogs were gods, and worshiped as such. God released enough frogs from the Nile so that the Egyptians could scarcely avoid stepping on them, as a direct affront to this worship practice.
Leviticus declares them unclean to eat.
And all that have not fins and scales in the seas, and in the rivers, of all that move in the waters, and of any living thing which is in the waters, they shall be an abomination unto you. Leviticus 11:10 (KJV)
According to atheistic biologist Richard Dawkins, the joints of the Lesser Spotted Weasel Frog continue to present a challenge to the Theory of Evolution insofar as their origin cannot be explained by gradual degrees.