LUNGLESS SALAMANDERS: Plethodontidae

PHYSICAL CHARACTERISTICS

The family of lungless salamanders includes the smallest and nearly the largest land-dwelling salamanders. These salamanders have no lungs and breathe through their skin. They have four toes on their front legs and four or five toes on their rear legs. They have a medium to long tail. Lungless salamanders are 1 to 14 inches (2.5 to 35 centimeters) long. The head is specialized for burrowing and for wedging under rocks and in stream beds. Some lungless salamanders have a long tongue that they can flick rapidly to catch prey. Lungless salamanders that live in caves never have eyes or skin coloring and may have oddly formed limbs and snouts. Other species start life as larvae, but as they go through metamorphosis their eyes disappear, the eyelids fuse together, and their skin loses its color.

Some lungless salamanders live as water-dwelling larvae for a few months to three years. Larvae (LAR-vee) are animals in an early stage that change body form in a process called metamorphosis (MEH-tuh-MORE-feh-sis) before becoming adults. Some species do not go through metamorphosis and spend their entire lives with the body form of larvae, but they can reproduce. At least three species never live as larvae and hatch from their eggs looking like small adults.

Scientists have found large numbers of miniature salamanders, mainly in the family of lungless salamanders. Most of these miniature species live on land throughout their lives, and many are secretive. New species continue to be discovered at a high rate. Many of these species are less than 1.2 to 1.4 inches (3 to 3.5 centimeters) long from tip of snout to tip of tail.

GEOGRAPHIC RANGE

Lungless salamanders live in southern Canada, much of the United States, and Mexico except the north-central parts of these countries. They also live in Central America and central South America. Most of the species live in the eastern and central parts of the United States. Six species live in the middle western Mediterranean region of Europe.

HABITAT

Lungless salamanders live in forest, woodlands, streams, springs, and caves. They thrive in wooded mountain areas. Some species live in deserts that receive fewer than 10 inches (25 centimeters) of rainfall each year. Others live in rainforests. Many species live in trees all or part of the time.

DIET

Lungless salamanders eat small crustaceans and insects but sometimes eat worms. Larger species sometimes eat smaller species. Lungless salamanders capture prey with an explosive flicking of their tongue. Crustaceans (krus-TAY-shuns), such as crayfish, are water-dwelling animals that have jointed legs and a hard shell but no backbone.

WHERE DID THE LUNGS GO?

Lunglessness is thought to have evolved as an adaptation for life in flowing water. Larvae are small, and lungs would tend to act as air sacs that might make the salamander float in the water. This would dislodge them from their food source and threaten their survival. Water in a stream is constantly being mixed with air, and salamanders can breathe through their skin, so there is little natural selection for keeping lungs.

BEHAVIOR AND REPRODUCTION

Lungless salamanders commonly live close together in large numbers and typically are the most numerous vertebrates (VER-teh-brehts), or animals with backbones, in a region. Lungless salamanders are secretive by day and active by night. They have small home ranges. The only ones that make seasonal travels are the few species that breed in water. Lungless salamanders that live in streams are more active than land-dwelling species, but most species can move quickly when disturbed, and they are good at escaping capture. The land-dwelling species, especially the tropical species, rely more on stealth than speed to avoid detection and capture and do not move as quickly as water-dwelling species. Some lungless salamanders are aggressive and fight to defend their territory.

All lungless salamanders have complex mating behavior, and mating can take many hours. More than half of the species are strictly land-dwelling and lay large eggs that they hide in spaces under rocks or logs, in moss mats, in balls of moss hanging in plants, in trees, and in plants that grow in trees. The eggs of these species hatch weeks after being laid, and the young look like small adults. Some species of lungless salamanders lay eggs in or near shallow water, typically moving water, and the eggs hatch into water-dwelling larvae that take a few months to three years to go through metamorphosis. A few species live their entire lives as larvae.

LUNGLESS SALAMANDERS AND PEOPLE

Lungless salamanders are not often seen by people.

CONSERVATION STATUS

The World Conservation Union (IUCN) lists one species of lungless salamanders as Extinct, thirty-one as Critically Endangered, eighty-three as Endangered, fifty-four as Vulnerable, and thirty-six as Low Risk/Near Threatened. Extinct means no longer in existence. Critically Endangered means facing extremely high risk of extinction in the wild. Endangered means facing very high risk of extinction in the wild. Vulnerable means facing high risk of extinction in the wild. Low Risk/Near Threatened means at risk of becoming threatened with extinction in the future.

The U.S. Fish and Wildlife Service lists four species of lungless salamanders as Endangered and three species as Threatened. Endangered means in danger of extinction throughout all or a significant portion of its range. Threatened means likely to become endangered in the near future.

DUSKY SALAMANDER (Desmognathus fuscus): SPECIES ACCOUNTS

Physical characteristics: Dusky salamanders are about 5.5 inches (14 centimeters) long from tip of snout to tip of tail. They have short legs and a stocky build. The hind legs are much larger than the front legs. The head is wedge shaped and has large eyes that bulge out. The jaw and neck muscles are thick. The tail has a low fin and ends in a sharp point. The tail grows back if it is pulled off by a predator, but it grows back with a blunt end rather than a sharp tip. Dusky salamanders usually are darker on the back than on the belly, which is cream colored. The back is mottled gray and black, striped with various shades of tan to yellowish brown to brown. A black stripe extends from the eye diagonally back to the angle of the jaw.

Geographic range: Dusky salamanders live in Quebec and New Brunswick in eastern Canada. Their range extends south and west as far as Indiana and South Carolina in the United States.

Habitat: Dusky salamander larvae live in springs, in small streams, and in water that has seeped up through the ground and collected in a pool. Adults spend some time on land but spend most of their time in seeped-up water or on the sides of springs and small streams, where they live among rocks or under logs.

Diet: Dusky salamander larvae mainly eat small invertebrates (in-VER-teh-brehts), or animals without backbones, such as the larvae of water-dwelling insects. They also eat tiny crustaceans and clams. Adults eat land-dwelling prey, mainly small insects and crustaceans, but they feed on water-dwelling insects when in the water. Larger dusky salamanders eat larger prey, but they continue to eat small prey. These salamanders sometimes eat one another, especially the larvae of others in their species. Adults capture their prey by rapidly flicking their tongues and snapping their jaws.

Behavior and reproduction: Dusky salamanders are active animals. They move very fast and are hard to catch. Most of their normal activity takes place in the early evening, but when conditions are warm and moist, these salamanders may be active throughout the night. By day dusky salamanders typically stay under cover. Dusky salamanders defend themselves from predators by remaining motionless or by biting.

Dusky salamanders mate on land. The male lures the female by rubbing her head with his body, waving his front legs, and placing himself alongside her and snapping backward. He approaches the female and positions her head at the base of his tail. He then walks forward, moving his tail back and forth while the female follows. The male releases a sperm bag, and the female takes it into her body. The female stores the sperm inside her. The eggs are fertilized when the female is ready to lay them in middle to late summer. She lays the eggs in clusters of five to thirty in moist, hidden places in seepage pools on rocks or at the edges of springs and small streams. The female guards the eggs until they hatch in about forty-five days. When the larvae hatch, they still have plenty of nutrients from the egg and do not feed immediately. Larvae grow slowly in the fall and winter but rapidly in the spring and go through metamorphosis in about nine months.

Dusky salamanders and people: Dusky salamanders have no known importance to people.

Conservation status: Dusky salamanders are not considered threatened or endangered. They are one of the most common salamanders in eastern North America. These salamanders adapt well to changes in their habitat as long as there are enough small streams. ∎

ARBOREAL SALAMANDER (Aneides lugubris): SPECIES ACCOUNTS

Physical characteristics: Arboreal (ar-BOR-ee-ul) salamanders have a heavily muscled head and body; a long, grasping tail; and long, grasping toes. The toes also have widened, somewhat curved tips. Arboreal salamanders are a little longer than 7 inches (18 centimeters) from tip of snout to tip of tail. Their large eyes bulge from the head in front of large jaw muscles. The head is nearly triangular. The upper and lower jaws have large, saber-like teeth with curved tips that can cause a serious wound. These salamanders are grayish brown to brown with yellow spots and a lighter belly. The spots can be small and scattered or large and close together.

Geographic range: Arboreal salamanders live mainly in California, United States, in the coastal mountains and valleys from the northwestern part of the state to the extreme northwestern part of Baja California Norte, Mexico. Some of these salamanders live on off-shore islands in the Pacific Ocean. Scattered groups live in the foothills of the Sierra Nevada.

Habitat: Arboreal salamanders live mainly in oak woodlands, where they use holes in the trees for nesting sites and for escape from dry conditions. These salamanders also live in sycamore woodlands near creeks in the southern parts of their range. Arboreal salamanders are commonly found under the bark of fallen oak logs, under rocks, and in holes in the ground.

Diet: Despite their large jaws and teeth, arboreal salamanders mainly eat small insects and crustaceans. Sometimes they eat slender salamanders.

Behavior and reproduction: Arboreal salamanders are aggressive. Both males and females have large jaw muscles and teeth that they use in fights over territory and against predators. These salamanders are good climbers, but most of their activity takes place on the ground.

Arboreal salamanders spend their entire lives on land. They do not enter water to breed. The females lay grape-like clusters of large eggs that are suspended from the roofs of underground holes, in large decaying logs, or in trees. The eggs hatch three to four months after they are laid, just before the fall rains. Young salamanders that look like small adults emerge from the eggs.

Arboreal salamanders and people: Arboreal salamanders have no known importance to people.

Conservation status: Arboreal salamanders are not considered threatened or endangered. ∎

TALAMANCAN WEB-FOOTED SALAMANDER (Bolitoglossa pesrubra): SPECIES ACCOUNTS

Physical characteristics: Talamancan (tah-lah-MAHNG-kahn) web-footed salamanders are stocky salamanders that reach a length of about 4 inches (11 centimeters) from tip of snout to tip of tail. The tail is about half of the total length. The toes are webbed, meaning there is skin between them, although the tips of the toes stick out beyond the webbing. Most of these salamanders are dark brown with a gray or black blotched or marbled pattern, but some of them are solid brown. The belly is dark gray but is lighter than the back. The throat is much lighter than the back and often has a slight yellow color. The legs are usually dark red or reddish orange.

Geographic range: Talamancan web-footed salamanders live in the Cordillera de Talamanca in central and eastern Costa Rica, generally at heights of 7,500 feet (2,300 meters) above sea level.

Habitat: Talamancan web-footed salamanders live under the bark of logs and under leaf litter in oak forests, but they also have survived in many areas where habitats have been destroyed. Large numbers of these salamanders have been found in local rubbish heaps. Talamancan web-footed salamanders also live in plants that grow in trees, in moss mats on trees, and by the sides of roads. These salamanders once were common at very high elevations, about 10,000 feet (3,050 meters), even in completely open areas, where they were found under rocks, slabs of concrete, and other objects, but in more recent years few have been found.

Diet: Talamancan web-footed salamanders eat small insects, which they catch with a very fast tongue that they flick with great accuracy.

Behavior and reproduction: Talamancan web-footed salamanders hunt and mate at night. Other than that, scientists know little about their behavior. When these salamanders hatch, they look like small adults. They do not hatch as larvae that have to change form before becoming adults. The females lay eggs all year in clusters of thirteen to thirty-eight eggs. The eggs are large and take a very long time to develop, partly because of the cool temperature of their mountain habitat. Females guard the eggs until they hatch.

Talamancan web-footed salamanders and people: Talamancan web-footed salamanders are the best known of the many tropical salamanders because they have been observed by generations of students in classes organized by the Organization for Tropical Studies, a group of scientists from all over the world that has three research stations in Costa Rica. These salamanders once were thought to be extremely tolerant of human activities and thrived even along heavily used roads, but they have disappeared from much of their range. Talamancan web-footed salamanders are still found in deep forests.

Conservation status: The IUCN lists Talamancan web-footed salamanders as Endangered, or facing very high risk of extinction in the wild. ∎

TWO-LINED SALAMANDER (Eurycea bislineata): SPECIES ACCOUNTS

Physical characteristics: Two-lined salamanders are small, thin salamanders with long, tapered tails. The eyes bulge out from the head. The color of these salamanders ranges from greenish yellow to yellow or orangish brown. Broad bands extend from behind the eyes along the trunk to near the tip of the tail. This band is marked with dark brown or black spots. On each side of the dark brown band is a brown or black stripe that extends from the eye well onto the tail. The sides of the salamanders are light with dark spots, and the belly is bright yellow with scattered dark spots. These salamanders are 5 to 5.5 inches (13 to 14 centimeters) long from tip of snout to tip of tail.

Geographic range: The geographic range of two-lined salamanders extends from northeastern Canada through the northeastern part of the United States to Ohio, West Virginia, and Virginia.

Habitat: The larvae of most two-lined salamanders live in small springs and water that has seeped up through the ground and collected in a pool. They sometimes live in ponds, where they live on the bottom. Young salamanders that have recently gone through metamorphosis and adults usually stay near streams in forested areas but move out into the forest, sometimes quite far from the water. As adults some two-lined salamanders stay on land for much of the year.

Diet: Larvae of two-lined salamanders eat the larvae of small water-dwelling insects but also eat small crustaceans. Adults feed mainly on small insects but also eat snails.

Behavior and reproduction: Two-lined salamanders look for food in the forest at night. Some scientists believe these salamanders guard their territory. Scientists believe two-lined salamanders mate on land and that females store sperm until it is time to lay the eggs. The fertilized eggs are laid one at a time under rocks in small streams. The females form nests but do not guard them. Nests can contain more than one hundred eggs, but there are usually about fifty eggs in a nest. Eggs take as long as ten weeks to hatch. After hatching, most two-lined salamanders live as larvae for about two years before metamorphosis is complete. Two-lined salamanders in the southern parts of the range are larvae for about one year.

Two-lined salamanders and people: Two-lined salamanders have no known importance to people.

Conservation status: Two-lined salamanders are not considered threatened or endangered. ∎

TEXAS BLIND SALAMANDER (Eurycea rathbuni): SPECIES ACCOUNTS

Physical characteristics: Texas blind salamanders have no eyes. They have red, feathery gills and a shiny white body with long, extremely thin legs. Gills are organs for obtaining oxygen from water. These salamanders reach a length of about 5 to 5.5 inches (13 to 14 centimeters) from tip of snout to tip of tail. The head is large and flat and has a broad, blunt snout.

Geographic range: Texas blind salamanders live only in a small area on the edge of the Edwards Plateau, near San Marcos in south-central Texas, United States.

Habitat: Texas blind salamanders live only underground in streams and pools in sinkholes and caves. A sinkhole is an area where the land over an underground river has collapsed and formed the entrance to a cave.

Diet: Texas blind salamanders eat snails and tiny crustaceans such as water fleas and cave shrimp.

Behavior and reproduction: Scientists know little about the behavior of Texas blind salamanders. These animals have been seen swimming in the water of caves and using their long limbs to grab and cling to the rocky cave walls. Scientists do not know how Texas blind salamanders reproduce.

Texas blind salamanders and people: Texas blind salamanders have no known importance to people.

Conservation status: The IUCN lists Texas blind salamanders as Vulnerable, or facing high risk of extinction in the wild. These salamanders were one of the first species named to the United States federal endangered species list. They become threatened when people remove the water from their habitat and by pollution from the land above the caves. ∎

BELL'S SALAMANDER (Pseudoeurycea bellii): SPECIES ACCOUNTS

Physical characteristics: Bell's salamanders are the largest lungless salamanders and almost the largest land-dwelling salamanders. They reach a length of nearly 14 inches (36 centimeters) from tip of snout to tip of tail. Bell's salamanders are shiny dark black and have a pair of red to reddish orange spots on the back of the head and paired rows of red to reddish orange spots along the back. There is usually a V-shaped mark at the beginning of the paired rows of spots. The tail is large and long. The legs are long and sturdy.

Geographic range: Bell's salamanders live in northern and central Mexico, usually at heights greater than 4,000 feet (1,220 meters) above sea level.

Habitat: Bell's salamanders live only on land under large surface objects such as logs and rocks in moist woods. They use burrows in the ground and can be found in holes in the sloping mounds of earth that line roadbeds in some areas.

Diet: Scientists believe Bell's salamanders eat insects, which they catch with a flick of their long, fast tongue.

Behavior and reproduction: Bell's salamanders are active at night. The females lay batches of more than twenty large eggs. Other than that scientists do not know how these salamanders behave or reproduce.

Bell's salamanders and people: Bell's salamanders have no known importance to people.

Conservation status: The IUCN lists Bell's salamanders as Vulnerable or facing high risk of extinction in the wild. ∎

FOR MORE INFORMATION

Books:

Bernhard, Emery. Salamanders. New York: Holiday House, 1995.

Griffiths, R. A. Newts and Salamanders of Europe. San Diego: Academic Press, 1996.

Gunzi, Christiane. Amphibians and Reptiles of North America. San Diego, CA: Thunder Bay, 1995.

Lawlor, Elizabeth P. Discover Nature in Water and Wetlands. Mechanicsburg, PA: Stackpole, 2000.

Llamas Ruiz, Andres. Reptiles and Amphibians: Birth and Growth. New York: Sterling, 1996.

Petranka, J. W. Salamanders of the United States and Canada. Washington, DC: Smithsonian Institution Press, 1998.

Periodicals:

Cohn, Jeffrey P. "Meet the Salamander." Americas (English Edition) (November-December 1993): 3.

Web sites:

"Aneides lugubris: Arboreal Salamander." San Diego Natural History Museum.http://www.sdnhm.org/fieldguide/herps/anei-lug.html (accessed on April 11, 2005).

"Arboreal Salamander, Aneides lugubris." Northern Prairie Wildlife Research Center.http://www.npwrc.usgs.gov/narcam/idguide/aneidelu.htm (accessed on April 11, 2005).

Bartholomew, P. "Aneides lugubris." Animal Diversity Web.http://animaldiversity.ummz.umich.edu/site/accounts/information/Aneides_lugubris.html (accessed on April 11, 2005).

Heying, H. "Plethodontidae." Animal Diversity Web.http://animaldiversity.ummz.umich.edu/site/accounts/information/Plethodontidae.html (accessed on April 11, 2005).

Munger, M. "Eurycea rathbuni." Animal Diversity Web.http://animaldiversity.ummz.umich.edu/site/accounts/information/Eurycea_rathbuni.html (accessed on April 11, 2005).

"Northern Two-lined Salamander: Eurycea bislineata." Northern Prairie Wildlife Research Center.http://www.npwrc.usgs.gov/narcam/idguide/eurybis.htm (accessed on April 11, 2005).

Vanwormer, E. "Eurycea bislineata." Animal Diversity Web.http://animaldiversity.ummz.umich.edu/site/accounts/information/Eurycea_bislineata.html (accessed on April 11, 2005).