Amphibians
Eastern Newt
Notophthalmus viridescens · also called red-spotted newt, red eft (juvenile stage)
The eastern newt is a small salamander with a complicated life. It hatches in water, then crawls out to spend years on land as a vivid orange “red eft,” then changes a third time and returns to the water as a green, finned adult. Along the way it carries a chemical defence borrowed from the same toolkit as the pufferfish.
Overview
Eastern newts are found across eastern North America, wherever there are fish-poor ponds, ditches, marshes, and slow woodland streams for breeding, surrounded by damp forest for the land stage. They are among the most abundant amphibians in the region, and one of the few salamanders often seen out in the open by day, thanks to the confidence lent by their toxicity.
Three lives
The eastern newt’s life cycle has up to three distinct forms:
- Larva. Eggs laid singly on submerged plants hatch into gilled aquatic larvae that grow through the summer.
- Red eft. In late summer the larva metamorphoses into a terrestrial juvenile — rough-skinned, bright orange-red, with no tail fin. The eft leaves the pond and lives on the forest floor for one to several years, occasionally over seven, dispersing the population.
- Adult. On maturing, the eft transforms again, developing a keeled swimming tail, smoothing and re-pigmenting its skin to olive-green with red spots and a yellow belly, and returning to water to breed and live out its life, up to about 15 years.
Where breeding ponds never dry out, many newts skip the eft stage and stay aquatic; where ponds are seasonal, the eft stage lets them wait out bad years on land.
Chemical defence
Newt skin contains tetrodotoxin-family toxins, potent blockers of nerve and muscle function. The red eft’s colour is a warning signal, and the strategy works — most predators avoid newts, and the notable exception, the common garter snake, has evolved resistance in an ongoing evolutionary arms race with newts on the Pacific coast (a different species there carries far more toxin).
Diet and role
At every stage the eastern newt is a carnivore, eating small invertebrates and, importantly, the eggs and larvae of other amphibians and of mosquitoes and midges. In fishless ponds, newts are often the top predator, and their feeding shapes the whole invertebrate community.
Status
The eastern newt is Least Concern, common, and adaptable. Local declines occur where breeding wetlands are drained or polluted, where introduced fish eat the larvae, and from road mortality during migrations and the amphibian diseases (chytrid fungus, ranavirus) that threaten amphibians globally. Its abundance and toxicity give it more resilience than many salamanders, but it still depends on the pairing of clean ponds with intact surrounding forest.
Eastern Newt: common questions
What is a "red eft"?
It is the juvenile land stage of the eastern newt. After hatching and growing as an aquatic larva, the newt transforms into a bright orange-red, rough-skinned form called an eft and leaves the water to live on the forest floor for one to several years — sometimes over seven. When it is mature it changes again, turning olive-green with a yellow belly, growing a finned tail, and returning to a pond as an aquatic adult. In some populations, especially where ponds are permanent, newts skip the eft stage entirely.
Are eastern newts poisonous?
Their skin secretes tetrodotoxin-type compounds — the same family of nerve poisons found in pufferfish — which make them distasteful and dangerous to eat. The vivid orange of the red eft is aposematic, a warning that advertises the toxicity, and predators that sample one generally leave newts alone afterwards. The toxin is not a danger from simply handling a newt, but you should wash your hands and never put fingers near your mouth or eyes.
How do newts find their way back to a pond?
Eastern newts are excellent navigators. Displaced experimentally, they orient back toward their home pond using several cues, most notably a magnetic compass — they can sense the direction and inclination of the Earth's magnetic field — supplemented by the smell of the water and by celestial and landmark cues. This lets an eft that has wandered far through the woods for years still return to breed where it hatched.
Can eastern newts regrow body parts?
Yes, to a remarkable degree. Like other salamanders, they can regenerate a lost leg or tail complete with bone, muscle, and nerves, and they can also regrow damaged tissue in the eye lens and retina, the jaws, the spinal cord, and parts of the heart. This has made newts and their relatives major subjects in regenerative-medicine research.