Shine a Light on the Cave Salamander
The cave salamander, also known as the spotted salamander (Eurycea lucifuga) is a species of salamander found throughout the eastern United States, particularly in the Appalachian mountains. As the name implies, they are most common in caves with exposed limestone or other calcifying rocks. However, they may also occur under rocks or logs, or in streams in deciduous forests; anywhere that's dark and moist.
The spotted salamander spends almost its entire life in these 'twilight zones'. Mating is believed to occur in summer or early fall, when male salamanders begin to seek out females by tracking their pheromones. Once a male finds a potential mate, he nudges her and rubs his chin on her head until she indicates she's receptive. At that point she straddles his tail while the two walk in tandem. The male then drops a spermatophore-- a sack full of sperm-- on the ground, and the female picks it up with her cloaca. The female lays a clutch of 5 to 120 eggs, but not until several months after fertilization between September and February.
The eggs take about 20 days to hatch, and larvae entirely aquatic, complete with gills and webbed fingers. Individuals can take anywhere from 6 to 18 months to fully develop, at which point they leave the water and become fully nocturnal. However, most individuals don't stray far from their original spawning territory, and adults do not maintain or defend set territories.
Despite their reclusive lifestyle, cave salamanders are quite striking. Adults are bright orange or red with black spots, and can be anywhere from 10 to 20 cm (4 to 8 in) in length. Over half of that length is taken up by the tail, and males have a longer tail than females. As lungless salamanders, E. lucifuga breathes through its skin and the tissues around its mouth-- while useful for an aquatic animal, this type of respiration makes it essential that the cave salamander remains in a wet environment.
Both larvae and adults are insectivorous, consuming a number of invertebrates including spiders, snails, beetles, earthworms, and ticks. Potential predators of the spotted salamander include bats, shrews, racoons, and snakes, though few specifics are known about the species' ecology. To deter these predators, E. lucifuga adopts a defensive posture in which they coil their body and wave their tail over their head. In addition, they secrete a foul-tasting substance from their skin, and their bright coloration likely warns potential predators that they won't make a good meal.
Conservation status: The IUCN has classified the cave salamander as Least Concern, although they are listed as Endangered in several of the American states in which they occur. The greatest threat to the species is thought to be human disturbance or habitat degredation from pollution of the water systems which flow through the caves where E. lucifuga resides.
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Photos
Todd Pierson
Michael Graziano
