Greater sirens are shaped like most salamanders, but their front limbs are short with only 4 toes, and they have no back limbs. This makes them look similar to eels. Their skin is olive or grayish brown with black speckles and yellow dashes, especially on their back. Their belly is lighter in color. Their body is round and their long, flat tail is about one third of the length of their whole body. Their heads have square jaws with one small eye on each side. They breathe through special gill organs behind their eyes but before their legs. Greater sirens are usually 62 to 77 cm long, but can get to be 97 cm long. (Behler and King, 1979; Conant and Collins, 1991; Hendricks, 2005; Sorensen and Moler, 2008)
Greater sirens are found in the southeastern United States, along the coast of the Atlantic Ocean and Gulf of Mexico. They are found from eastern Virginia, south to the bottom of Florida, and west to southwestern Alabama. There are some greater sirens near the Rio Grande River in southern Texas and northern Mexico, but scientists aren't completely sure how these two groups are related. (Conant and Collins, 1991; Hendricks, 2005)
Greater sirens are different from many kinds of salamanders because they spend their whole lives in the water and never live on land. They are found in water environments that have good shelter. This includes swamps with lots of plants, ponds, ditches, streams, and larger lakes. They travel to more shallow water when they lay eggs. Young greater sirens live in thick plants, and move to deeper water as they get older. Adults spend most of their time near the bottoms of pools, in plant roots and branches, or under sunken logs. If the water dries up, they burrow into the lake or stream bed and become almost completely inactive so they don't dry out. (Conant and Collins, 1991; Hendricks, 2005; Leviton, 1971)
Greater sirens keep the same features during their whole life. Their gills are outside their body during their whole life. They never get back legs. When they are born, they are about 11 mm long. They have stripes at birth which they slowly lose during the first year they are alive. They are also born with a red or yellow triangle mark on their nose. Young greater sirens are brighter and more spotted than adults. (Hendricks, 2005; Sorensen and Moler, 2008)
Scientists don't know much about the mating systems of greater sirens. (Hendricks, 2005)
Greater sirens are able to have their own young when they are 2 to 3 years old. They breed once a year between February and March, depending on their environment. Females lay about 500 eggs that look like small grapes and stick to each other. The eggs develop for for about 2 months and hatch in April or May. (Behler and King, 1979; Hendricks, 2005; Sorensen and Moler, 2008)
Female greater sirens guard their eggs in shallow water until they hatch. Then, they return to deeper water. After that, the parents don't contribute any more to their development. (Hendricks, 2005)
Scientists don't know much about the lifespan of greater sirens, but one greater siren that lives in the Cincinnati zoo is at least 25 years old. (Hendricks, 2005)
Greater sirens are only active at night. During the day, they hide out in thick plants near the bottom of the lake or stream where they live. When the water dries, up, they burrow into the mud. Then, they give off dead skin cells to make a protective layer around themselves and stop them from drying out. Greater sirens can live up to 5.2 years like this, and lose up to 80% of their body mass. When the water comes back, they recover quickly. Greater sirens have lungs as well as gills, and gulp air from the water's surface. They can also give off and take in air through their skin, so sometimes they crawl out of the water to rest on a log or on the shores. Their small front limbs prevent them from traveling far on land. (Hendricks, 2005; Sorensen and Moler, 2008)
Scientists don't know much about the sizes of the areas where greater sirens live. (Hendricks, 2005)
Greater sirens live in water where it is difficult to see, so seeing is probably not their most important sense. They have an extra smelling organ that helps them detect prey, and can sense vibrations in their environment. They might also be able to sense changes in electricity found in the water. Greater sirens are usually found by themselves, so scientists don't know much about how they communicate with each other. When predators come close to them, they hiss. (Fritzsch and Neary, 1998; Hendricks, 2005; Sorensen and Moler, 2008; Sullivan, et al., 2000)
Greater sirens eat mostly other animals. They prey on insects, crustaceans, gastropods, bivalves, spiders, mollusks, crayfish, and small fish. They also eat some algae. (Hendricks, 2005; Sorensen and Moler, 2008)
Greater sirens are eaten by American alligators and red-bellied mud snakes. They make various sounds to intimidate predators. They yelp, hiss, croak, and make a sound similar to a young duck. Using their muscular tails, they can make a quick getaway. As a last resort, they can deliver a painful bite to ward off predators. (Hendricks, 2005; Sorensen and Moler, 2008)
Greater sirens eat insects and other invertebrate species. They can become infected with platyhelminth parasites, like flatworms called Ophiotaenia sireni and Progorgodera foliata and also trematodes. (Brooks and Buckner, 1976; Hendricks, 2005; Sorensen and Moler, 2008)
Greater sirens don't have any known negative impacts on humans.
Greater sirens benefit humans by limiting the number of invertebrates that live in the water as well as insects. (Sorensen and Moler, 2008)
Greater sirens are common in the central parts of the places where they live, but uncommon at the edges of their range. They are considered endangered in Maryland. Because they spend so much of their lives in the water, it is difficult to know how many there are. Possible threats to their numbers are habitat loss to farming and building by humans, and pesticide pollution. (Hendricks, 2005)
Kimberley McKenzie (author), Sierra College, Jeremy Wright (editor), University of Michigan-Ann Arbor, Catherine Kent (editor), Special Projects.
Behler, J., F. King. 1979. The Audubon Society Field Guide to North American Reptiles and Amphibians. New York: Knopf.
Brooks, D., R. Buckner. 1976. Some platyhelminth parasites of sirens (Amphibia: Sirenidae) from North America. The Journal of Parasitology, 62: 906-909.
Conant, R., J. Collins. 1991. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Third Edition, Expanded. New York, NY: Houghton Mifflin Company.
Fritzsch, B., T. Neary. 1998. The octavolateralis system of mechanosensory and electrosensory organs. Pp. 878-922 in H Heatwole, E Dawley, eds. Amphibian Biology, Volume 3, Sensory Perception. Chipping Norton, New South Wales, Australia: Surrey Beatty and Sons.
Hendricks, R. 2005. Siren lacertina Linnaeus, Greater Siren. Pp. 141, 361, 364, 372, 644, 911-4 in M Lannoo, ed. Amphibian Declines: The Conservation Status of United States Species. Berkeley: University of California Press.
Leviton, A. 1971. Reptiles and Amphibians of North America. Garden City, New York: Doubleday.
Sorensen, K., P. Moler. 2008. Greater Siren, Siren lacertina. Pp. 263-5 in J Jensen, C Camp, W Gibbons, M Elliott, eds. Amphibians and Reptiles of Georgia. Athens, Georgia: University of Georgia Press. Accessed November 20, 2011 at http://books.google.com/books?id=F4ffa47N9wwC&pg=PA265&lpg=PA265&dq=greater+siren+male+female&source=bl&ots=Fu92LOsFq8&sig=MubvlRASvax-rv7_sTcQcVvzUiA&hl=en&ei=xA-uTpjeJIvYiALAvPmyCw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CDAQ6AEwAg#v=onepage&q&f=false.
Sullivan, A., P. Frese, A. Mathis. 2000. Does the aquatic salamander, Siren intermedia, respond to chemical cues from prey. Journal of Herpetology, 34: 607-611.