Western Lesser Siren

Siren intermedia nettingi
Family

Sirenidae (sirens) in the order Caudata (salamanders)

Description

An eel-like, permanently aquatic salamander with external gills, small eyes, small forelimbs with four toes, and no hind limbs at all. The 3 pairs of external gills are red or grayish red and have a bushy appearance. Body color varies from dark gray to brown to almost black. The belly is lighter than the back. Tiny dark brown or black flecks or spots are usually scattered over the back. There are 31 to 38 costal grooves (vertical grooves on the sides of the body). Sirens produce a large amount of mucus on their skin. This, plus their ability to wriggle and squirm, makes them almost impossible to hold. They do not bite and are completely harmless to humans.

Similar species: The three-toed amphiuma (Amphiuma tridactylum) lacks feathery external gills and has fore- and hind limbs; in Missouri, its range is limited to the Bootheel. Both of these salamanders can be distinguished from eels and lampreys (which are fish) by their limbs with fingers, tiny eyes, and lack of fins and scales.

Size

Length: 7–16 inches.

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Siren in a bucket
Last Siren Song
Lesser sirens are aquatic salamanders that have long eel like bodies that can get up to 2 feet long.

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Heron and Siren
Last Siren Song
Although this may not be a common sight, sirens are another part of the food chain. This great blue heron is having lesser siren for its next meal.

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Small yet resilient siren
Small Yet Resilient Siren
Lesser sirens burrow in the mud during drought and reemerge when habitats become flooded again.
Habitat and conservation

This permanently aquatic eel-like salamander lives in sluggish streams, ditches, ponds, sloughs, and swamps. By day it hides under clumps of aquatic plants and submerged roots or branches. It forages at night. If the pond or slough begins to dry up, the animal burrows into the bottom mud. As the mud dries, the siren’s skin glands produce a thick mucus layer that becomes a parchmentlike cocoon that prevents the salamander from drying out. It can aestivate this way for several months, until rains return.

Foods

Forages at night for small crayfish, aquatic insects, snails, and worms. This species can apparently obtain food by filter feeding through bottom material and in aquatic vegetation, gleaning small crustaceans this way.

image of Western Lesser Siren Distribution Map
Distribution in Missouri

Along the eastern edge of the state, along the Mississippi River, and in the Bootheel of southeastern Missouri.

Life cycle

Little is known of the courtship and mating of this species. In spring, each female lays from 100 to over 1,500 eggs in small pockets in the bottom mud of a pond or ditch or in aquatic vegetation. It takes two years for a western lesser siren to reach maturity.

Human connections

If you are fishing and catch a lesser siren (or any other amphibian), cut the line and release it unharmed. Most amphibian populations are declining, none are venomous, and none threaten our fisheries. They are an integral part of our aquatic fauna.

Ecosystem connections

The western mudsnake of southwestern Missouri specializes in eating our two eel-like amphibians (the amphiuma and the lesser siren). The slippery amphibian thrashes wildly, but the snake pokes its prey with its pointy tail tip. This makes the amphibian uncurl and easier to swallow.