The distinction between a newt and a salamander is a common source of confusion, as both are amphibians characterized by a lizard-like appearance and a prominent tail. Understanding the difference requires looking beyond their general appearance to their scientific classification, specific physical features, and the variations in their life cycles.
Understanding the Taxonomic Grouping
The simplest way to clarify the relationship is through taxonomy: all newts are a type of salamander, but not all salamanders are newts. The broad group encompassing both is the order Caudata, which contains over 700 species of tailed amphibians, all scientifically considered salamanders. Within this order, there are multiple families of salamanders, such as the lungless salamanders and the mole salamanders.
Newts belong to the family Salamandridae and, more specifically, the subfamily Pleurodelinae. This means that the term “newt” is a common name applied to a specific, related group of salamanders, not a separate scientific classification. Other salamander families, such as Ambystomatidae (mole salamanders) or Plethodontidae (lungless salamanders), do not contain newts.
Distinct Physical Characteristics
The physical differences between the two groups often relate to their lifestyle, particularly the amount of time they spend in the water. Many newts, especially in their aquatic adult phase, have rougher, warty, or granular skin that looks drier than that of most other salamanders. Conversely, non-newt salamanders possess skin that is generally smooth, slick, and moist.
Newts that live a semi-aquatic or fully aquatic adult life often develop a tail that is vertically compressed, or paddle-like, which aids in swimming. Terrestrial salamanders, such as the North American mole salamanders, typically have a more rounded, robust tail and well-developed digits on their feet suited for walking or digging in soil. These morphological variations are adaptations to the different niches they occupy.
Differences in Life Cycles and Habitats
A major distinction lies in the life cycle, which is a defining characteristic of newts. Many newts exhibit a triphasic life cycle that includes an aquatic larva, followed by a terrestrial juvenile stage known as an “eft,” before returning to water as a semi-aquatic or aquatic adult. The eft stage is a period where the juvenile newt lives entirely on land, often possessing brightly colored, rough skin.
Many other salamander species often skip this distinct terrestrial eft stage, moving directly from the aquatic larval phase to a terrestrial adult or remaining aquatic throughout their lives. For instance, some lungless salamanders lay eggs that hatch directly into miniature versions of the adults, skipping the larval stage entirely.
The habitat preferences are also divergent, with newts typically returning to water annually to breed. Many terrestrial salamanders may only visit water briefly for reproduction, or, in some cases, not at all.
Salamanders that are mainly terrestrial often burrow or seek shelter under logs and leaf litter. Newts, particularly during their terrestrial eft phase, will also walk on land, often dispersing widely from their breeding grounds.