Facts About Salamanders

There are more than 700 known species of salamander, ranging from the Chinese giant salamander, which can reach nearly 6 feet (1.8 m) long, to tiny pygmy salamanders in the genus Thorius that measure under an inch.

Salamanders are one of the few vertebrate groups capable of regenerating lost limbs, as well as tails, eyes, and even parts of internal organs like the heart and spinal cord — a trait that makes them a major focus of regenerative-medicine research.

Salamanders have moist, permeable skin that allows them to absorb oxygen and release carbon dioxide directly through it, a process called cutaneous respiration.

While many species are aquatic or semi-aquatic, living in or near water, others are fully terrestrial, thriving in forests, grasslands, or underground burrows.

Salamanders are ectothermic (cold-blooded), so they regulate their body temperature by moving between sun and shade rather than generating heat internally.

Many salamanders perform elaborate courtship displays before mating, and some species show parental care, with females of certain species able to store sperm for months before fertilizing their eggs.

Some salamanders defend themselves with skin toxins. The rough-skinned newt produces tetrodotoxin, a potent neurotoxin that can be lethal if ingested by predators.

Most salamanders are carnivorous, feeding on insects, worms, and other small invertebrates; some of the largest species will even take small vertebrates like mice or fish.

A phenomenon called neoteny lets some salamanders, most famously the axolotl, retain juvenile features — including external gills — into adulthood, so they stay aquatic for life instead of metamorphosing into a land-dwelling adult form.

Because their moist skin makes them highly sensitive to pollution, temperature, and habitat changes, salamanders are considered bioindicator species that help scientists gauge an ecosystem's health.

Salamanders communicate with potential mates and rivals through visual cues like body posture and coloration, as well as chemical pheromones and physical vibrations.

The Japanese giant salamander, one of the largest amphibians alive, can live for 50 years or more in the wild and even longer in captivity.

Newts are actually a subgroup of salamanders — all newts are salamanders, but not all salamanders are newts. Newts typically have rougher, drier-looking skin and spend more of their adult life in water.

Some salamander species reproduce by laying eggs that hatch into aquatic, gilled larvae, which later undergo metamorphosis; others give live birth or skip the larval stage entirely through direct development.

The axolotl (Ambystoma mexicanum) is critically endangered in the wild, surviving in only a small network of canals and lakes near Mexico City, even though it is common in captivity worldwide.