The Eastern Newt
Created | Updated Oct 7, 2010
- Order Caudata
- Family Salamandridae
- Genus Notophthalmus
- Species Notophthalmus viridescens
Appearance
The adults are yellow-brown or olive-green and can even become dark brown with rather dull yellow underbellies. They are covered in tiny black spots. Adult males have a high tail fin and dark spots on the back legs during the breeding season. Their skin (which is less moist than in some of their relatives) has a rough bumpy texture making them easier to hold than other salamanders. They range from seven to 14cm long.
The juveniles (efts) are red-orange with the same bright black-orange markings as the adults; however, they tend to have fewer numbers of the tiny black spots. They measure 3.5 to 8.5cm in length.
Subspecies
There are four subspecies of the eastern newt:
Broken-striped Newt
(Notophthalmus viridescens dorsalis) - These newts have red spots which join together to form a broken line along either side of the body. They are the smallest of the subspecies. The eft stage is skipped completely with larvae developing into mature adults; therefore, adults are often neotenic1. The broken-striped newt is found along the coastal plains of the Carolinas.
Central Newt
(Notophthalmus viridescens louisianensis) - They have fewer, much smaller spots of red or orange along the back which are not completely ringed with black. Some may have no spots at all. The efts, when present, are uncommon and range from dull orange to dark brown. This newt can be found as far afield as the western Great Lakes region of Canada, westward into Minnesota and Kansas, and south to the gulf coast.
Peninsula Newt
(Notophthalmus viridescens piaropicola) - This newt is a darker form of the eastern newt which has no red spots at all. Skin colour is greenish-brown to near black and heavily speckled with black spots. The eft stage is usually skipped so neoteny is frequent. It is only found in peninsular Florida.
Red-spotted Newt
(Notophthalmus viridescens viridescens) - This is the largest of the subspecies and grows up to 14cm in length. The efts are the brightest in skin colour. Both adults and juveniles have large bright black outlined orange spots along their back. Its habitat ranges from northeast Canada to the eastern Great Lakes and south through the Appalachians to Mississippi, Alabama, and Georgia.
Lifecycle
Eastern newts have a 'three-stage' lifecycle: aquatic larvae, terrestrial efts, and aquatic adult.
Breeding takes place in April and May. The male will position himself above and forward of the female, gripping her sides just behind her forelegs with his hind legs. He rubs the female's snout with the side of his head. Fanning motions with the tail are often described as a mating 'dance'. Each of the 200 to 400 eggs are individually placed on the submerged leaves and stems of vegetation in vernal pools, wetlands, and ponds; they hatch within three to four weeks.
Larvae
The aquatic larvae have laterally compressed tails, olive coloured skin, and feathery gills. The hatchlings range in length from 7mm to 9mm and have fairly smooth skin with little toxicity. Although the length of the larval period and the size at metamorphosis varies, they usually transform into a terrestrial eft stage after three to five months. By August or September the aquatic larvae change, losing their gills, into a juvenile stage called a red eft.
Efts
The newly transformed newt leaves the water to spend several years on land as the brightly coloured eft, only returning to the water as a mature newt. They begin as aquatic juveniles and then grow into terrestrial juveniles. Curiously, the aquatic adults lack gills, and instead have well-developed lungs, limbs, and eyelids.
The sexually immature red eft is nocturnal (active during the night) and more active 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. After two to three years, the eft migrates back to breeding sites transforming into adults - their skin becomes damper, coloration becomes darker and body form changes.
Adults
At the adult stage they are truly aquatic, they lose their bright colour and develop a powerful finned tail. As a mature newt they return to the water to breed and remain there for the rest of their life. The adult newt has a life span between five and 15 years
Habitat
The adults are aquatic and live in slow-moving streams, lakes, unpolluted ponds, small lakes, ditches, and marshes that have lots of vegetation and submerged logs. They hibernate under logs or under water and may remain active under the ice. The efts are terrestrial and live in damp woodlands.
They are rarely seen out of water, usually just resting on logs below the surface of a pond or lake. Because of their skin colour they are fairly well camouflaged and hard to spot amounst the water plants they like to rest and hunt in.
The efts are easier to see then the adults. After a heavy rain they can be seen foraging for food in their woodland habitat.
The Hunter and the Hunted
Adult newts can sometimes be seen in shallow water hunting for food, often foraging both day and night. They eat worms, insects, molluscs, crustaceans, and amphibian or fish eggs and larvae, or that of other such creatures.
Efts feed mainly at night, on spiders, caterpillars, flies, worms, smaller insects, crustaceans, and invertebrates that they find in the leaf litter.
Newt larvae feed on smaller larvae, daphnia, snails, mosquito larvae, and other small aquatic invertebrates.
Predators include birds, leeches, mammals, fish, and other amphibians. Because fish readily eat newts and their eggs, they are most abundant in ponds without fish.
The newt’s bright coloured spots and the eft’s red skin colour, which warns about the toxic skin secretions, deter many predators.
Conservation
As with all creatures, the best environment for them is a natural one. Creating a wildlife garden for mammals, birds or insects with a pond for aquatic animals, can provide a habitat for wildlife to thrive in.
Experienced aquarium owners may want to add newts to improve the natural environment of their tanks. They need plants, rocks or driftwood to break the surface of the water. Filters should be kept to a minumum and the flow dispersed with rocks. The aquarium temperature should be 18-23 deg; C (60-74 deg; F) in the summer months and 5-10 deg; C (40-50 deg; F) for the winter months, although newts often feed under ice, so a drop in temperature is not of great concern. Efts are entirely terrestrial and will require a moist woodland terrarium, with the same temperature requirements of the adult newts. When they mature they will need to be re-housed into an aquarium. Feeding commercial fish or amphibian pellets as opposed to their natural diet is not recommended.
