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Green Salamanders

Rebecca John, Auburn University
Green salamanders (Aneides aeneus) are terrestrial amphibians found in the Appalachian Mountains of eastern North America. They are typically associated with limestone or sandstone rock outcroppings and cliffs surrounded by hardwood trees that buffer them from harsh environmental changes. In Alabama, they can be found in the northern portion of the state associated with the Cumberland Plateau and the Tennessee Valley and Ridge. They are the only salamanders in North America with green coloration.
Green salamanders are in the salamander family Plethodontidae, which refers to all salamanders without lungs. The many species of lungless salamanders breathe through their skin and must stay in moist habitats to take in oxygen, including the endangered Red Hills salamander. Green salamanders are active at night, when they are less likely to lose body moisture, and so they are able to live in drier environments than most other salamanders, such as crevices in rock and bark. They belong to the genus Aneides, the climbing salamanders, and are the only representative of this genus in the eastern half of the United States. The genus name means "shapeless" referring to their elongated form, and the species name aeneus means "bronze," which refers to their yellowish-green spotted dorsal (upper body) coloration. Each salamander has a unique dorsal pattern that does not change throughout its lifetime, save for scarring. The ventral (underside) surface of green salamanders is translucent and shows their internal organs. Males can also exhibit an orange coloration on their chins during the spring breeding season to visually attract females. Green salamanders can be further identified by their flattened head and body, long limbs, prehensile tail, and square toe-tips that help them climb and tuck themselves into cracks.
Adults of both sexes grow, on average, to about 5.5 inches (~140 millimeters) in length. They are thought to live up to 15 years of age and possibly longer. Green salamanders grow slowly, taking up to seven or eight years to mature sexually. Males can be distinguished from females by the length of their teeth, with males having elongated teeth used during courtship. Once they reach sexual maturity, females breed biannually (every other year) due to the very high energy requirements of producing and protecting eggs. Because of this, the species has a very slow population growth rate.
Green salamanders breed in spring from March to May. Females lay eggs in June and July, and eggs hatch in September and October. In the northern portions of their range, green salamanders hibernate from November to February deep within rock crevices. In the southern range of the species, such as Georgia, Mississippi, and Alabama, they can be active on warm days in winter. Unlike most amphibians, which lay eggs in the water and have aquatic larvae, green salamanders have what is known as direct development, meaning that their young develop into the adult form within the egg. Females begin to lay eggs in mid-June in rock crevices or under tree bark. They produce approximately 17 to 21 eggs over a 24-hour period. Eggs are suspended from the roof of a crevice with strands of mucus. Females stay with the eggs, not leaving their brooding crevice even to eat, for the duration of development. Scientists think that females defend the eggs from predators and protect them from fungus and bacteria by rubbing their head on the eggs and cleaning them. If females are removed from their brooding crevices, the eggs decay within days. Eggs hatch between 75 and 90 days, depending on latitude, beginning at the start of September and continue to hatch through October, depending on when they were laid. Hatchlings, which can take up to two days to emerge, look like miniature adults and are about a half inch (~1 centimeter) in total body length. Some hatchlings have blue dorsal markings that turn green as they age.
Members of this species likely eat a variety of invertebrates that are small enough to fit into their mouths, but their diet has not been studied well. Predators include snakes, such as ringneck snakes and young black rat snakes, that are small enough to get into crevices of trees and rocks. Spiders also prey on green salamanders. There are probably other predators but they are not well documented. Because green salamanders are excellent climbers, they are thought to be highly mobile and capable of moving large distances overnight. Scientists do not know if males or females have different patterns of movement within their territories. It is likely juveniles disperse the following spring after hatching, but studies are still needed to confirm this. Natural history, behavior, and genetic studies may help answer these questions on local and regional scales.
Green salamanders are a species of conservation concern for Alabama. The International Union for Conservation of Nature (IUCN) categorizes their status as "Near Threatened." The Center for Biological Diversity group has petitioned for the species to be listed under the Endangered Species Act owing to habitat loss and unexplained declines in localized populations. The U.S. Fish and Wildlife Service is currently gathering information to determine if protection is warranted.
Additional Resources
Canterbury, Ronald A., and Thomas K. Pauley. "Time of Mating and Egg Deposition of West-Virginia Populations of the Salamander Aneides Aeneus." Journal of Herpetology 28 (December 1994): 431-34.
Gordon, Robert E., and Richard L. Smith. "Notes on the Life History of the Salamander Aneides aeneus." Copeia 3 (September 15, 1949): 173-75.
Gordon, Robert E., "A Contribution to the Life History of the Plethodontid Salamander Aneides aeneus." The American Midland Naturalist 3 (1952): 47, 666-701.
Waldron, Jayme L., and W. Jeffrey Humphries. "Arboreal Habitat Use by the Green Salamander, Aneides Aeneus, in South Carolina." Journal of Herpetology 39 (September 2005): 486-92.
Waldron, Jayme L., and Thomas K. Pauley. "Green Salamander (Aneides Aeneus) Growth and Age at Reproductive Maturity." Journal of Herpetology 41 (December 2007): 638-44.
Published:  December 19, 2016   |   Last updated:  December 19, 2016