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.
Numbat
Numbats are insectivores and eat an exclusive diet of termites. An adult numbat requires up to 20,000 termites each day. The only marsupial fully active by day, the numbat spends most of its time searching for termites. It digs them up from loose earth with its front claws and captures them with its long, sticky tongue. Despite its banded anteater name, it apparently does not intentionally eat ants; although the remains of ants have occasionally been found in numbat dung, these belong to species that themselves prey on termites, so were presumably eaten accidentally, along with the main food. Known predators on numbats include the carpet python "Morelia spilota imbricata", introduced red foxes, and various falcons, hawks, and eagles.