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.
Italian crested newt
In early stages of development in amphibians, it has been discovered that convectional gas transport, the method through which hemoglobin is carried throughout the body, is an unnecessary process. This is important because it indicates that the coupling of ventilator gas transport and hemoglobin gas transport are independent mechanisms and not yet coupled as they are in adulthood. An example of this difference is seen in the response to hypoxia between organisms at differing developmental stages. In juvenile newts, there is no cardiovascular response in conditions of hypoxia.