Newt
Newts, as with salamanders in general and other amphibians, serve as bioindicators because of their thin, sensitive skin and evidence of their presence (or absence) can serve as an indicator of the health of the environment. Most species are highly sensitive to subtle changes in the pH level of the streams and lakes where they live. Because their skin is permeable to water, they absorb oxygen and other substances they need through their skin. Scientists study the stability of the amphibian population when studying the water quality of a particular body of water.
Salamanders in folklore
A newt is a type of salamander, and they are traditionally associated with witchcraft. In William Shakespeare's famous play "Macbeth", the witches use the "eye of newt" as the first ingredient stirred in their cauldron. However, the famous line in "Macbeth" is actually referring to a series of plants. Eye of newt refers to mustard, which reiterates the link between salamanders and fire as mustard seeds are used as a "fiery" spice.