The Sword-tail newt (Cynops ensicauda) has recently been placed on Japan's Red List of Threatened Amphibians. This newt has a very small range and can only be found in some of the southernmost islands of Japan. Sometimes, Sword-tail newts are called Fire-bellied Newts, not to be confused with the common Chinese and Japanese species, because of their bright orange bellies which serve as a warning to predators that they are poisonous. They can be differtiated from these two species by their large size, broader head and (against Japanese Fire-Bellies) smoother skin. These newt ranges from brown black above, occasionally with an orange dorsal stripe. Some individuals may have light spotting or speckling on their back. They
Sword-tailed newts grow from 5 - 7 inches and are considered to be the largest living members of their genus. Females are usually smaller than males and have a proportionately longer tail.
The sword-tailed newt is only found on the Ryukyu Archipelago, and island chain of the southern coast of Japan, as well as on many smaller surrounding islands. This newt makes it habitat in slow, cool, stagnant bodies of water, such as ditches, ponds, streams and rice patties. There are two known subspecies of Sword-tailed newt, Cynops ensicauda ensicauda and Cynops ensicauda popei. Due to the subtropical climate of its native habitat, it is more tolerant of high temperatures than other Cynops. Habitat destruction is the main cause of the decrease in populations of these newts.