Project Description

Greater Siren

Siren lacertina

Aquarium Location



Typically found in a variety of aquatic habitats, including swamps, streams, rivers, lakes, bays and even ditches. In addition, this species is one of the few amphibians in the world known to tolerate brackish water.


Limited to the southeastern U.S., from northern Virginia south along the Atlantic coastal plain.


Greater sirens are one of the most effective of all freshwater aquatic predators. They have been known to feed on crayfish, worms, snails, aquatic insects and small fish. In addition, they supplement their diet by ingesting quantities of aquatic vegetation while engulfing prey items.

Fun Facts

Has relatively weak forelimbs and lacks hind limbs, making travel across land virtually impossible. The greater siren only emerges from the water when it is absolutely necessary.
Greater sirens have lived up to 25 years in captivity.
Sirens are superficially considered the most primitive group of salamanders because of their appearance (external gills and only two legs), but their natural history is poorly known.
The scientific name Siren laceratian comes from Latin, literally meaning ‘mermaid’ and ‘little lizard’.
Adults may reach well over three feet in length.

Cool Adaptation

This strange eel-like amphibian has external gills that it uses to breathe. Unlike many other amphibians (frogs, toads, salamanders), sirens remain in the water for their entire lives. It has always been assumed that this trait indicates that sirens are probably one of the most primitive of all the amphibians, but very little is actually known about this species’ natural history. Although limiting them to a fully aquatic lifestyle, a siren’s external gills give it the unique ability to aestivate under extreme drought conditions. If an individual’s habitat dries up, it will burrow down into the muddy bottoms and create a cocoon of mucus and shed skin around its body that will prevent water loss. This keeps the area around its external gills moist, which allows the animal to breathe. Amazingly, these animals can slow down their body functions, some dramatically (up to 70%) and can live in this state for more than a year until their habitat refills with water.

Conservation Connection

It is very difficult to gauge the trends of greater siren populations because there are no past studies of this species that could be used for comparison. It is believed that the biggest threat to greater siren populations in the future is the loss of wetland habitats in the southeastern United States. Using aquatic herbicides to clear waterways of vegetation has also seemed to have affected certain populations. In addition, greater sirens are known to hunt small fish, which can lead to individuals being hooked or entangled by fishing line and is thought to have had a detrimental effect on their population as well. The greater siren is considered uncommon throughout its range, although may be abundant in some regional locations of suitable habitat. There currently is no special concern/status for the conservation of this species.