"Giant
Salamanders"Sirens and Amphiumas
"Giant
Salamanders"
Sirens and Amphiumas
When we think of salamanders, we usually think
of small creatures that scurry away when we turn over rotten logs or other debris.
Most people in the Southeast don’t realize that southeastern wetlands are home
to two groups of huge aquatic salamanders, sirens and amphiumas. Two
species, the greater siren and the two-toed amphiuma, may grow to massive
sizes – the largest individuals reaching more than three feet in length. These
amphibians spend most of their time hiding in weed-choked wetlands, slow-moving
streams, and Carolina bays. People rarely encounter these two species, although
fishermen occasionally catch enormous black salamanders and assume that
they are American eels (a species of fish). Amphiumas, or "congo
eels" as they are often called, can be common in many southeastern wetlands.
Two-toed amphiumas occur on the Coastal Plain across much of the Southeast.
These animals have miniscule 
front
and back legs with two toes on each foot. They feed on crayfish, aquatic invertebrates
and other small animals that share their habitat. When wetlands dry up in extremely
dry weather, these salamanders can be found deep underground in moist mud, where
they remain until the wetland refills. Because sirens are similar in appearance
and often occupy the same habitats as amphiumas, greater sirens are sometimes
mistaken for two-toed amphiumas. Two key differences are that sirens
only have front legs, and they also have feathery external gills. In general,
sirens are a bit shorter than amphiumas and have a stockier body. Like
amphiumas, sirens also feed on crayfish and other small animals. When
wetland habitats dry, sirens go underground, and they have the ability to form
a cocoon around their 
bodies
to hold in moisture. This adaptation allows them to stay dormant in dry weather
until the rains refill the wetlands. Sirens and amphiumas belong to the
extensive "hidden biodiversity " of the Southeast. It is hard to believe
that two such large animals are so infrequently seen. Although these two species
are fairly common, very little is known about their natural history. More research
is needed to determine what role they play in the ecosystem.
Photos provided by David Scott.
This information is provided as a public service by the Savannah River Ecology Laboratory Outreach Program.
