Eastern Newt Species AccountNotophthalmus vindescens
The eastern newt is a small- to medium-sized salamander with two irregular rows of reddish spots bordered by black circles. The spots run down the length of the back and are present at all stages of the newt's life. However, the general appearance of the eastern newt is somewhat different in each of its three distinct life stages: larva, eft, and adult. As developing larvae in the water, newts are small, with faint red or yellow spots, bushy gills, and large tail fins. As they grow, they lose their gills, and in most populations, their tail fins disappear and they emerge from the water as brightly colored orange or red efts.
Newts are the only type of salamander in the eastern United States and Canada that go through such an intermediate eft stage. During this stage, they are highly visible animals, frequently seen walking out in the open woods during the day. After several years of terrestrial existence as immature efts, they reach maturity and return to the water to breed with other adults. In many permanent ponds and lakes, they spend the remainder of their adulthood in the water. However, in some ponds, they move in during the breeding season and back out during winter or dry periods.
In the adult stage, newts usually are dull brown, and have a yellow belly with numerous small black dots. Aquatic adults have flattened tails that are more appropriately shaped for swimming than the rounded tails of the efts. During the breeding season, the tail fin of the male gets very broad, and he often waves it around in the water, seemingly displaying his breeding status. Males also have a series of dark, hardened pads on the inside of their hind legs for clasping females. Adult newts usually range in size from 6-11 cm(2 1/2 4 1/2 in.), while the brightly colored efts range from 3.8-9 cm (1 1/2 3 1/2 in.).
The red salamander, when young, often is bright orange. However, the red salamander has black dots, and similar to most other species of salamanders, has slimy skin and visible grooves along its sides between the front and rear legs. In the eastern region of North America, north of Georgia, the eastern newt is the only salamander that has red dots with black borders. In addition, very few other salamanders walk around in the open woods in broad daylight as boldly as do the bright orange newts in the eft stage.
In both the adult and larval stages, eastern newts are aquatic animals that often live in great numbers in unpolluted, permanent bodies of water with plenty of aquatic plants. The species is extremely flexible, however, and can be found in temporary ponds, ditches, streams, and agricultural ponds. Eastern newts occur near sea level and along the entire eastern coastal plain; they are also numerous in many higher-altitude ponds and mountain lakes, occurring at elevations above 1,000 m (3,300 ft). The efts are found in a variety of terrestrial habitats, but mainly in moist woodlands that border the ponds where they originated. On damp days, hundreds of brightly colored efts and dull-colored adults may be out patrolling the forest floor.
Where and When
The eastern newt is common in eastern North America from Nova Scotia to Minnesota and southward to Florida and the Gulf Coast. This species occurs in coastal habitats, at higher elevation inland sites, and just about everywhere in between. Aquatic adults are active most of the year. In early spring, as the ice is melting in northern regions, they begin to congregate around the shorelines and around vegetation in preparation for breeding.
They remain active throughout the summer and fall and in many areas can be seen swimming during the winter months. Occasionally, they will swim toward a hole cut into the ice of a frozen pond. In temporary ponds or in warmer regions, adults often go back on land during dry periods and throughout the winter, but return in very early spring to breed. Throughout the summer, larval newts can be seen swimming, until fall, when they transform into efts and move out of the water into the surrounding uplands. The bright orange terrestrial efts remain actively foraging until late fall, after which they settle under logs, in crevices, or in burrows until early spring.
The eastern newt has a complex, and sometimes very long, life cycle. In the North, courtship and breeding take place in the water in early spring, usually from March through May. Some additional mating may occur in the fall, but females lay eggs only in spring. During mating, a male entices a female with a complex courtship dance, and embraces her for up to several hours with his rear legs. The female then follows along after him and picks up the packets of sperm that he deposits on the pond bottom. Once the sperm packets are brought inside her cloaca, the 200 to 400 eggs waiting there are fertilized.
Over a period of up to several weeks, the female attaches these eggs singly to objects in the water. The eggs hatch around four weeks later, and the tadpoles develop into small newts over the next three months. They then emerge from the water and usually move to surrounding woods to begin a long existence as immature terrestrial salamanders, which are called efts. During this stage, which can last from two to seven years, efts are brightly colored and often are unconcealed, walking around in broad daylight. The bright color is an obvious warning to predators, meant to remind them that newts secrete toxic chemicals that make them distasteful or even harmful to eat.
As the efts approach maturity several years later, their color becomes greenish-brown, their skin becomes smoother, their tails flatten out, and they return to the water to breed with other adult newts. On land, efts eat insects, worms, and other ground-dwelling animals small enough to swallow. In the water, the newts' diet includes mosquito larvae, aquatic insects, leeches, clams, and snails. The total life span of an eastern newt can be greater than ten years, and sometimes much longer.
The eastern newt is widespread throughout the eastern United States and southeastern Canada. In a wide variety of habitats, newts are an important component of both aquatic and terrestrial communities. As larvae, efts, and adults, they eat an impressive diversity of insects and other small creatures. They also are a food source for some predators, such as reptiles that apparently are not bothered by newt toxins. Because the terrestrial environment is so important to newts in many populations, their conservation depends on preservation of aquatic and surrounding upland habitats.
Bright colors, such as red, orange, and yellow, often serve as a caution sign to potential predators, warning them of the toxicity of their prey. This vivid display of danger is called aposematic coloration. In the eastern newt, the bright orange skin of the eft contains glands that secrete a chemical that is offensive to other animals, often irritating their mouths, and potentially making them sick. The quickness of the negative reaction probably saves many newts, which may be left alone after the first bad taste. This helps explain why eastern newts walk around, seemingly without care, on the surface of the forest floor, boldly announcing their presence with flashy colors.Use this background information on the eastern newt with the Reptile and Amphibian Defense Strategies lesson plan.
Excerpted from Hands-On Herpetology.
Provided by the National Science Teachers Association.
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