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Eastern Newt

Notophthalmus viridescens

What do they look like?

Aquatic larvae have flattened tails, olive colored skin, and feathery gills. Hatchlings range in length from 7 to 9 mm and have smooth skin that isn't toxic. Eastern newts usually transform into a terrestrial "eft" stage after 2 to 5 months as an aquatic larva. The eft is reddish-orange in color with two rows of black-bordered red spots. It has well-developed lungs, limbs, and eyelids. The eft's skin is dry and somewhat rough and its color is a signal to predators that it is toxic. The eft has a long-slender body with a flattened tail and ranges in length from 3.4 to 4.5 cm. The eft usually grows enough to breed after 2 to 3 years on land. These adult newts are yellowish-brown to greenish-brown and have black-bordered red spots. The belly color is yellow with black spots. The adult newt is slightly moist (just enough to keep its skin from drying out), with rough skin. Its size ranges from 7 to 12.4 cm long and it has small eyes with a horizontal pupil.

  • Range length
    7 to 12.4 cm
    2.76 to 4.88 in

Where do they live?

The eastern newt is one of only a few species of true salamanders native to North America. It is found throughout most of eastern North America, from Atlantic coast to the Great Lakes and south to Texas, Alabama, Georgia, and Florida.

What kind of habitat do they need?

Eastern newts inhabit both deciduous and coniferous forests. Immature larvae and adult newts live in small bodies of freshwater (ponds, small lakes, ditches, and marshes), usually with mud bottoms. Adults can survive on land if their watery habitat dries up; adults may move onto land when the water is low. The juvenile "eft" stage lives in lakeshore and woodland habitats and is often seen in forest litter on rainy nights.

  • Aquatic Biomes
  • lakes and ponds

How do they grow?

Eggs develop for 3 to 8 weeks, depending on water temperature. In early fall, 3 to 4 months later, the aquatic larvae lose their gills, develop sac-like lungs, and emerge onto land as an eft. Two to 3 years later, the eft develops a powerful, flattened tail and returns to the water to breed. Adults remain in their pond or lake for the rest of their life, if the water is permanent, or spend dry seasons on land and move back to the water in the spring (the wet season). Some eastern newt populations skip the eft stage and immediately transform into breeding adults. There are some coastal populations of eastern newts that can breed while still in their gilled, larval form or the eft form. (Behler and King, 1979, 1998; Lazell, 1976; Petranka, 1998; Richmond, 1997)

How do they reproduce?

The breeding season begins in late winter and lasts until early spring. Females are attracted by a male's spots, which he uses to lure a female towards him. He also makes fanning motions with his tail and emits a pheromone (sexual odor). When a female approaches, the male climbs onto her back and begins to rub his head on her snout. Males then deposit a sperm packet on the bottom of the pond and the female moves forward to pick it up. Males might compete with each other, but it is usually females who choose their mates.

It can take several weeks after breeding for females to lay their eggs. They lay a few eggs each day in different places. Females lay between 200 and 400 single, jelly-covered eggs on submerged plants each season. As soon as the process is finished, the female newt swims away leaving her eggs to survive on their own. Both males and females reach sexual maturity around the age of 3.

  • How often does reproduction occur?
    Eastern newts breed once per year.
  • Breeding season
    The breeding season varies with latitude, beginning in late winter and lasting until early spring.
  • Range number of offspring
    200 to 400
  • Range time to hatching
    3 to 8 weeks
  • Average age at sexual or reproductive maturity (female)
    3 years
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    2000 days
    AnAge
  • Average age at sexual or reproductive maturity (male)
    3 years
  • Average age at sexual or reproductive maturity (male)
    Sex: male
    2000 days
    AnAge

Eastern newts do not provide care for their young after the eggs are laid.

  • Parental Investment
  • no parental involvement
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female

How long do they live?

Eastern newts have a lifespan of up to 12 to 15 years. However, mortality is high in eggs and larvae. (Petranka, 1998)

How do they behave?

Eastern newts move quickly in water, but are slow on land. Larvae stay mostly in one place, settling at the bottom of the water to hide. The eft is active at night, especially on rainy nights. In dry, sunny weather, the eft will find a cool, moist place to rest and crawl out to feed when damp, darker weather approaches. The adult newt returns to the water and spends the rest of its life there, often foraging both day and night. Winter is spent underground, unless the adults are in permanent water. Eastern newts can often be seen foraging in winter beneath the ice.

How do they communicate with each other?

Eastern newts use both chemical and visual cues to locate food. Adults seem to rely more on visual cues when feeding. Eastern newts also use chemical cues, visual cues, and touch to communicate when breeding.

What do they eat?

The aquatic larvae eat small invertebrates including water fleas, snails, and beetle larvae. Efts eat small invertebrates, mainly those found in leaf litter, including snails, springtails, and soil mites. Adult newts eat mainly midge larva and other aquatic immature stages of insects.

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • mollusks
  • terrestrial worms
  • aquatic crustaceans
  • zooplankton

What eats them and how do they avoid being eaten?

Predators of eastern newts include birds, carnivorous mammals, fish, and other amphibians, but many of them are deterred by the newt's toxic skin secretions.

What roles do they have in the ecosystem?

Eastern newts are important predators of small invertebrates in the freshwater ecosystems of eastern North America. (Petranka, 1998)

Leeches and other parasites attack eastern newts, which sometimes leave the water and begin to bite at and scratch parasites to get them off.

Commensal or parasitic species (or larger taxonomic groups) that use this species as a host
  • leeches (Hirudinea)

Do they cause problems?

There are no negative affects of eastern newts on humans. Their skin is toxic, so they should never be eaten or handled with broken skin, but they are not very toxic to humans.

  • Ways that these animals might be a problem for humans
  • injures humans

How do they interact with us?

Eastern newts may benefit humans by helping to control populations of aquatic insects, including mosquitoes. They play an important ecological role in freshwater and woodland habitats. Eastern newts are sometimes kept as aquarium or terrarium pets and have even been commercially collected for the pet trade.

  • Ways that people benefit from these animals:
  • pet trade

Are they endangered?

There is no special status listed for eastern newts. Populations have declined as a result of habitat degradation, but they are still common in many parts of their range. Adult newts will inhabit man-made bodies of water, including those with fish, as their toxic skin may help to reduce their risk of being eaten by fish.

Some more information...

Contributors

George Hammond (editor), Animal Diversity Web.

Shannon Riemland (author), Michigan State University, James Harding (editor), Michigan State University.

References

Behler, J., F. King. 1979, 1998. National Audubon Society Field Guide to North American Reptiles and Amphibians. New York: Chanticleer Press, Inc..

Dunn, L., A. Hagen. 1999. "Habitat Rehabilitation in the Great Lakes" (On-line). Accessed November 2, 1999 at http://www.on.ec.gc.ca/wildlife/docs/habitat-rehabilitation4-e.html#red.

Lazell, J. 1976. This Broken Archipelago: Cape Cod and the Islands, Amphibians, and Reptiles.. New York: Quadrangle/New York Times Book Company.

Petranka, J. 1998. Salamanders of the United States and Canada. Washington, D.C., USA: Smithsonian Institution Press.

Richmond, A. 1997. "The Red-Spotted Newt" (On-line). The Connecticut River Homepage. Accessed 03/14/06 at http://www.bio.umass.edu/biology/conn.river/newt.html.

 
University of Michigan Museum of ZoologyNational Science Foundation

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Riemland, S. 2000. "Notophthalmus viridescens" (On-line), Animal Diversity Web. Accessed October 01, 2014 at http://www.biokids.umich.edu/accounts/Notophthalmus_viridescens/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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