What is the Difference Between Salamanders & Newts? [Updated]
While salamanders and newts may initially appear similar and it can be confusing to tell them apart, they are actually incredibly different. Below, we’ll break down the key differences between these two unique and important organism types, from appearance to behaviours and everything in-between.
Salamander & Newt Classification
Both salamanders and newts are amphibians, and when comparing the two, it’s easiest to remember the rule that all newts are salamanders, but not all salamanders are newts! Salamander diversity is complex – salamanders are split into several families in the order Urodela, or clade Caudata. The family Salamandridae contains true salamanders and newts, with newts classified into the subfamily Pleurodelinae.
Typical of amphibians, both salamanders and newts start their life cycle with an aquatic larval stage. Newts then generally develop into semi-aquatic or aquatic adults, while salamanders are often found living in moist terrestrial environments during the adult stage of their lives. Of course, there are exceptions to each rule and it’s best to research individual species when comparing them, as this group has a stunning amount of diversity. There are approximately 500 species of salamanders and 60 species of newts that have been identified, with scientists estimated there are many, many more yet to be discovered.
Just a few examples of the complicated diversity amongst this order include the eastern newts, Notophthalmus viridescens which have 3 stages in their life cycle: an aquatic larval stage, a juvenile terrestrial stage (known as efts), and then back to an aquatic stage as an adult. There are also species of salamanders that are aquatic for their entire lives, such as the eastern hellbender (Cryptobranchus alleganiensis) and the mudpuppy (Necturus maculosus) which does not even undergo metamorphosis.
The word salamander means “fire lizard” in Greek, which comes from the early misconception that European fire salamanders (Salamandra salamandra) were fire resistant, due to the fact that they were mostly seen when they emerged from their hiding places in logs used as firewood. Meanwhile, the word newt translates to “small, lizard-like animal” which comes from Old English eft or ewte.
Salamander and Newt Appearance & Size
Salamanders and newts can be differentiated by a few physical characteristics. Newts generally have webbed feet and a tail shaped like a paddle, which makes them well adapted for life spent mostly in the water. Newts also have rougher skin than salamanders, and some species are even dry or warty in appearance. Finally, newts exhibit more sexual dimorphism than salamanders. In some species males grow a prominent crest for display, such as in the European great crested newt (Triturus cristatus), which looks rather like a tiny dragon.
Salamanders often have longer tails and feet with developed digits for walking, climbing, and digging. Salamanders are more often confused with lizards due to their appearance, however they completely lack the scales or claws of lizards. Depending on the species, either adult salamanders or newts may have developed lungs, gills, or both. The lungless salamanders in the family Plethodontidae lack lungs and breathe air entirely through their moistened skin.
Salamanders and newts vary in size – as there are many more species of salamanders than newts, size variation in salamanders is greater. The vast majority of salamanders are generally around 6 cm in length. The smallest salamander, a pygmy salamander Thorius arboreus of Mexico reaches only 0.6 in/1.7 cm in length. Giant Salamanders in Asia can grow to impressive sizes. The largest recorded Chinese Giant Salamander, Andrias davidianus, was 5.9 ft/1.8 m long! In contrast, the largest known newt is the Spanish ribbed newt Pleurodeles waltl, which grows to 1 ft/30 cm long.
Salamander and Newt Diet & Nutritional Requirements
Salamanders and newts are all carnivores and opportunistic predators. Depending on what is available in their habitat, they might be active predators or use an ambush (sit and wait) method to catch their food. They mainly feed on aquatic and terrestrial invertebrates, and as slow-moving predators they are more likely to eat slow invertebrates such as worms, slugs, and snails.
They have also been known to eat small crustaceans, fish, and flying insects that have been trapped in the water. Most species of salamander and newt have tiny teeth, even in their larval stages, which are used for grasping food rather than chewing.
Wild salamanders or newts can be great for home ponds because they act as natural pest control. In captivity, aquatic species can be given commonly available feed such as brine shrimp, bloodworms, and insect larvae, while mealworms, crickets, and feeder fish are good for terrestrial species.
Salamander and Newt Behaviour & Breeding
Many species of both salamanders and newts are nocturnal, hiding in wood or rocks during the day and emerging to feed at night, so they rely on good night vision. Cave dwelling species of salamanders live in the dark their entire lives, so they have evolved reduced eyes and instead rely on their senses of smell, touch, and hearing.
Late winter through early spring in the Northern Hemisphere is the best time to see wild salamanders and newts because this is when adults are emerging from hibernation and are the most active for breeding, sometimes traveling across the land during the rain to find vernal ponds and marshes. Reproductive behavior is similar for salamanders and newts.
Unlike frogs and toads, salamanders and newts are generally not vocal during breeding season. They primarily rely on the use of pheromones to find a mate. Courtship, breeding and egg laying takes place in the water, so depending on the species terrestrial adults return to the water, sometimes traveling a distance to their home habitat just to reproduce. Usually, males will perform an elaborate courtship display for the female and then deposit a spermatophore for eggs to be fertilized internally. While most lay clusters of eggs in the water, a few species give birth to live offspring!
Most salamander and newt lifespans average between 5 to 25 years, but some species of salamander can be extremely long lived. The oldest known salamander is the blind cave salamander Proteus anguinus, which has been recorded living over 70 years in captivity and is predicted to live an average of 100 years in the wild, due to its limited need for activity and slow metabolism.
Salamander and Newt Habitats
Salamanders and newts are distributed throughout the Northern temperate and Neotropical regions. They can be found in North America, Europe, Asia and north Africa and are limited by Arctic climates. The U.S. contains the largest number of species of salamanders and newts.
A general trait shared amongst salamanders and newts is that they thrive in cool, moist environments, thus they are most often found living in wetland habitats such as ponds, streams, swamps and marshes. However, salamanders have filled all sorts of unexpected niches. Several species are specially adapted to life in caves. Others, such as the Inyo mountain salamander, Batrachoseps campi, are found in localized habitat surrounded by inhospitable arid mountain regions. The arboreal salamander, Aneides lugubris, is a great climber, seen at heights of up to 60 feet, and lays its eggs in tree cavities and logs instead of in the water.
As a fun fact, the most unexpected place newts have survived is not even on earth – the Japanese red-bellied newt has been sent to space to study the effect of microgravity on embryonic development!
Salamander and Newt Threats
Like other amphibians, salamander and newt skin is permeable, so they absorb water and other products of the environment. This unfortunately makes them highly sensitive to environmental pollution from human activities. They are also highly affected by habitat destruction, as wetlands are delicate and rapidly disappearing ecosystems. Finally, some species, including the well-known fire salamander, have been in decline due to the spread of the chytrid fungus, a deadly pathogen that thrives in wet environments and infects the skin of amphibians.
Amphibians in general are a group of priority conservation concern. Many species of salamanders and newts are listed as critically endangered, and even for species that are least concern, population trends are generally decreasing. The best hope for amphibians is through worldwide wetland conservation, and cooperative species breeding and reintroduction programs. Even keeping an amphibian-friendly garden in your home is a small act that can help native salamander and newt populations.
To attract wild salamanders and newts to a garden, it helps to create a natural habitat for them by keeping a pond or bog garden, or a wildlife pond, making piles of rocks and brush for them to hide in, planting native plant species, and avoiding the use of pesticides and herbicides.
Salamander and Newt Natural Predators
Salamanders and newts provide a food source to many species of mammals, birds, reptiles, and are sometimes even preyed on by other amphibians, especially when they are in their larval stage. While some are neutral in coloration to camouflage into their environment, others are brightly colored to signal that they are poisonous to eat.
All salamanders and newts have the ability to secrete toxins which aid in deterring predators. The genus Taricha, which includes four species of newts located in western North America, can secrete tetrodotoxin, an extremely potent neurotoxin which has can be lethal to humans who come in contact with it. Interestingly, tetrodotoxin has convergently evolved in pufferfish as well. Some predators have adapted by developing a tolerance to these toxins, such as with the predator-prey relationship between the common garter snake and the extremely poisonous rough-skinned newt.
An interesting fact about this group of animals is that salamanders and newts have the ability to regenerate easily lost limbs, which is a survival tactic to escape from predators. A spotlight species in research is the axolotl (Ambystoma mexicanum), a neotenic salamander which is popular in laboratory studies due to its healing ability to regenerate not only limbs, but sometimes even vital structures such as the brain, spine, and tissues of the eye and heart! This research is being applied to human medicine, and has helped provide understanding of how injuries heal and even potential for future human limb regeneration.