What is the difference between a salamander and a lizard?
At first glance salamanders appear to be a type of lizard. However, this is not true. Salamanders are their own distinct group of animals belonging to the order Caudata. Even though they do superficially resemble lizards, there are several important differences that separate the two.
One visual cue is that lizards usually have external ear openings and clawed toes. Salamanders lack both of these features. Salamanders are also amphibians, while lizards are reptiles. The main differences between reptiles and amphibians are that reptiles are covered in dry scales or scutes, while amphibians have moist, permeable skin. Amphibians also produce eggs that are dependent for the most part on water and moisture, while reptiles have shelled eggs that are adapted for life on land. Most amphibians undergo a metamorphosis from juvenile water breathing forms to adult air breathing forms, whereas reptiles do not.
An Ancient Lineage
Salamanders first appeared on Earth approximately 160 million years ago during the Jurassic period, making them one of the oldest groups of land vertebrates still alive today. They have survived multiple mass extinction events, including the one that wiped out the dinosaurs 66 million years ago. Today, there are over 700 different species of salamanders found across North and South America, and in the temperate parts of Northern Africa, Asia, and Europe. Salamanders are absent from the southern regions of these continents, and there are no salamanders in Australia or Antarctica.
Salamanders reach their greatest diversity in the Appalachian Mountains region of eastern North America. This area is considered one of the most important salamander biodiversity hotspots on the planet. In some Appalachian forests, the total biomass of salamanders actually exceeds that of all the birds and mammals combined, which gives you a sense of just how numerous and ecologically significant they are.
What is the difference between a salamander and a newt?
Many individuals wonder what the difference is between a newt and a salamander. Newts are actually a type of salamander. All newts are salamanders, but not all salamanders are newts. Newts generally belong to the subfamily Pleurodelinae within the family Salamandridae. One distinguishing characteristic of many newt species is that they tend to have rougher, more textured skin compared to the smooth, moist skin of most other salamanders. Newts are also more likely to spend significant portions of their adult lives in water, while many other salamanders are primarily terrestrial as adults.
Remarkable Abilities
Salamanders possess some truly extraordinary biological abilities. Perhaps the most famous is their power of regeneration. Unlike most vertebrates, many salamander species can fully regenerate lost limbs, tails, parts of their heart, eye lenses, and even portions of their brain. Scientists have been studying salamander regeneration for decades in hopes of unlocking medical applications for humans.
The axolotl (Ambystoma mexicanum), a salamander native to the lakes near Mexico City, is particularly famous for this ability and has become one of the most important model organisms in biological research. Axolotls can regenerate almost any body part with remarkable fidelity, including spinal cord tissue, making them invaluable to the study of regenerative medicine.
Breathing Without Lungs
One of the most fascinating groups of salamanders is the family Plethodontidae, also known as the lungless salamanders. These animals have no lungs at all and breathe entirely through their skin and the lining of their mouths. This makes them incredibly sensitive to changes in their environment, particularly to pollutants and changes in moisture levels. Plethodontidae is actually the largest family of salamanders, comprising over 470 species, which means that the majority of the world's salamander species breathe without lungs.
Size and Diversity
Salamanders come in an astonishing range of sizes. The smallest species in the world is Thorius arboreus from Mexico, which measures just about 17 millimeters in total length and could comfortably sit on a human fingernail. At the other end of the spectrum, the Chinese Giant Salamander (Andrias davidianus) can reach lengths of nearly 1.8 meters (almost 6 feet), making it the largest amphibian on Earth. The Japanese Giant Salamander (Andrias japonicus) is nearly as large and has been revered in Japanese culture for centuries.
Salamanders display an incredible variety of colors and patterns. Many species are brightly colored as a warning to predators that they are toxic. The Fire Salamander (Salamandra salamandra) of Europe, with its striking black and yellow pattern, is one of the most recognizable examples. Other species are masters of camouflage, blending seamlessly with leaf litter, moss, or the rocky streambeds they inhabit.
Learn More
Discover why salamanders matter to the environment and human health, learn about the threats they face including climate change and the devastating Bsal fungus, and find out how you can help protect these incredible creatures. If you have found a salamander in your home, visit our guide on what to do.