If ever a salamander was an unsung hero, it is the amphiuma. Reaching lengths of 4 feet, amphiumas are longer than any other amphibian in the Western Hemisphere. So few people ever see one, they do not even have a familiar common name. They are generally referred to by their scientific name (Amphiuma), although some people call them conger eels. They have their own taxonomic family distinct from all other salamanders. Another oddity resides in their DNA. A human has less than 4 percent of the amount of DNA as an amphiuma. What this means genetically about us, or about amphiumas, is still up for scientific debate.
Finding an amphiuma is an awesome experience, even to naturalists who see lots of unusual animals. My grandson Parker captured one on a recent field trip. These secretive creatures inhabit swamps and lowlands, spending their entire lives in the mud and waters of places where few people ever go. They are found only in the coastal states from Virginia to Louisiana.
Three other kinds of seldom-seen giant salamanders are also native to the eastern United States. One is the greater siren, the largest being more than 3 feet long. Two others, the hellbender and the mudpuppy (or waterdog), also qualify as giant salamanders, although neither gets as long as the biggest amphiumas and sirens. The mudpuppy, reaching a length of 18 inches, is primarily a northern species found in lakes, ponds and rivers. Hellbenders are bulky creatures that can reach 2 feet, 6 inches long. They live in cold mountain streams and rivers from Alabama to New York. The Japanese giant salamander, the world’s largest, is closely related to the hellbender. Individuals can be more than 5 feet long.
Despite their enormous size relative to other amphibians, sirens and amphiumas have minuscule legs with toes. An amphiuma more than a yard in length will have legs less than an inch long and no thicker than a toothpick. Both amphiumas and sirens are short-legged, dark-colored, slippery creatures, but distinguishing one from the other is easy. Sirens have only two of the seemingly useless legs, whereas amphiumas have four. In addition, sirens have external, visible gills; amphiumas have openings alongside the head that lead to internal gills.
Sirens and amphiumas are slimy animals that seldom leave the water; they would quickly dehydrate if left on dry ground. Most people trying to pick one up for the first time cannot hold on to it. Amphiumas can deliver a serious, cutting bite. Knowing how to handle them is important if you decide to pick one up. Both salamanders live in aquatic habitats that can dry up completely during long-term droughts. What do great big water-dwelling salamanders do then? As their lake home dries up, they burrow into the mud. They secrete a slimy body covering that hardens into a cocoon. This keeps them moist from a few months to more than a year. When the rains return and the cocoon is exposed to water, the siren or amphiuma emerges to begin feeding on aquatic insects and other invertebrates that have also survived the drought.
Sirens and amphiumas kept as pets have been known to live for decades. No one knows how long they can live in the wild. Their courtship and mating behavior are also a mystery, even for specimens kept in captivity. Amphibian biologists are not sure how closely related sirens are to other salamanders. Some argue that sirens are not salamanders at all but some other type of amphibian.
America’s giant salamanders bring to the fore two ecological insights. One, scientists know relatively little about the biology of some of the largest animals in our midst, which means we still have much to learn about the natural world. Second, some creatures here in the U.S. are as fascinating in their own way as any exotic species with a starring role in a nature show.
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