Amphibians
Black-bellied Salamander
Desmognathus quadramaculatus · also called black-bellied dusky salamander
The southern Appalachians hold more kinds of salamander than anywhere else on Earth, and in the coldest, fastest streams the biggest of them is a heavy, black-bellied animal that props itself on the bank at night and grabs whatever comes past, including the other salamanders.
Overview
Desmognathus quadramaculatus is the largest of the dusky salamanders, reaching 13 to 21 cm, with a stout body, strong jaws, and a jet-black belly. It lives in and beside cold, fast, rocky mountain streams in the southern Appalachians, and it is lungless, breathing entirely through its skin.
An ambush hunter
At night it sits at the stream edge, front half out of the water and propped on its forelegs, and lunges at passing prey. It eats insects and crayfish but also smaller salamanders — seal, two-lined, dusky — and smaller black-bellied salamanders, making it a top predator in the stream.
Slow to grow
The female guards her eggs under a stream rock, and the aquatic larvae take three to four years to transform, so the animal matures late.
Status
Least Concern and abundant in good streams, though sensitive to siltation and warming, and depleted in some areas by heavy collection for the live fishing-bait trade.
Black-bellied Salamander: common questions
Is the black-bellied salamander dangerous, and can it bite?
It is completely harmless to people, with no venom and no toxic skin secretion strong enough to matter. It is, however, one of the few salamanders large and bold enough to give a noticeable bite. A big black-bellied salamander held in the hand will often twist around and clamp down with its jaws, which can pinch and, on a finger, occasionally break the skin. It is not aggressive toward humans and would much rather escape into the stream; the bite is a defensive reflex from an animal used to grabbing and holding struggling prey.
Why does it eat other salamanders?
Because it can, and because in its habitat other salamanders are an abundant, protein-rich food. The southern Appalachian streams where the black-bellied salamander lives contain some of the highest salamander diversity and density anywhere on Earth, with several smaller species sharing the same rocks and banks. The black-bellied salamander grows large enough, and has jaws strong enough, to take a two-lined or a seal salamander whole, and it also eats smaller black-bellied salamanders. This makes it a genuine predator within the salamander community, not just an insectivore, and its presence changes the behaviour of the smaller species.
How can I tell a black-bellied salamander from other stream salamanders?
Size is the first clue, since a full-grown black-bellied salamander is noticeably bigger and chunkier than the two-lined, dusky, or seal salamanders it lives alongside. Turn it over and the belly is uniformly black or very dark, without the mottling or pale throat of related species. It also has the down-turned snout and the pale line running from the eye to the angle of the jaw that mark the dusky salamander group, a keeled, laterally flattened tail for swimming, and often a row of paired pale spots down the back in younger animals. It is almost always found right in or beside fast water.
Why are stream salamanders like this one used as fishing bait?
In parts of the southern Appalachians, large salamanders, locally called spring lizards, have long been collected and sold as live bait for bass and trout, and the black-bellied salamander, being the biggest, is a prime target. Commercial bait collectors can remove very large numbers from a stream, and because the species grows slowly, matures late, and does not disperse far, a heavily harvested stream can take many years to recover. Several states now regulate or prohibit the commercial collection of stream salamanders for this reason.