The salamander capital of the world
The Great Smoky Mountains National Park is the undisputed center of salamander biodiversity on Earth. The cool, moist forests, deep leaf litter, and abundant streams create the perfect conditions for these amphibians. The park hosts around 30 species, representing five distinct families of salamanders. This incredible diversity is primarily driven by one group: the lungless salamanders of the family Plethodontidae.
As their name suggests, these animals have no lungs. They absorb oxygen directly through their skin and the lining of their mouths, a strategy that requires a constantly damp environment. The ancient geology and varied elevations of the southern Appalachians have, over millions of years, created thousands of isolated, wet mountain hollows. Salamander populations became trapped in these "islands," separated from their neighbors by drier ridges. This geographic isolation is a driver of allopatric speciation, causing the gene pools of different populations to diverge. Over time, this process has produced a radiation of distinct species, many of which are found only in one specific mountain range or valley.
The sheer number of these creatures is staggering. In some parts of the forest, salamander densities can be as high as two individuals per square meter. By total weight, the salamander population in the Great Smoky Mountains National Park exceeds that of all other vertebrates—including bears, deer, and birds combined.
A living laboratory of evolution
The Jordan's Salamander (Plethodon jordani) provides a clear example of this evolutionary process at work. What appears to be a single species is actually a complex of visually similar, yet genetically separate, species and subspecies. The Red-cheeked Salamander (Plethodon jordani) is endemic to the high elevations of the Great Smokies and is found nowhere else on the planet. Closely related forms, like the Southern Appalachian Salamander (Plethodon teyahalee), occupy adjacent ranges.
These salamanders are not passive inhabitants of the forest floor. They are significant predators of invertebrates, helping the nutrient cycle of the ecosystem. Lungless salamanders possess nasolabial grooves, tiny slits that run from their nostrils to their upper lip, which they use to detect chemical signals from prey and potential mates.
This remarkable biodiversity is a historical artifact; evolution is ongoing. Between 2020 and 2024, researchers discovered four new species of lungless salamanders within the park. The Great Smoky Mountains are a dynamic natural laboratory for studying how new species arise.