Its hard to miss the bright Red Efts in the woods this year. With all the rain this year they are wandering widely. Efts are the terrestrial form of the Eastern Newt (Notophthalmus viridescens). Like most amphibians, they have to keep their skin moist so they are most often seen crawling around during rainy days.
In later summer aquatic larvae may transform either directly into the adult aquatic stage or become a terrestrial eft. Bright orange and red, the efts live on land for up to four years. They eat small insects, springtails, snails, and other arthropods. As they grow older they become darker and darker until they begin to look almost like an adult Eastern Newt. They return to the water where they will mate and live the rest of their lives.
Why such an obvious, bright orange color? This is aposematic coloration, warning coloration that makes a poisonous animal particularly conspicuous and recognizable to predators. Their tough skin contains high concentrations of tetradotoxin, a neurotoxin and strong emetic.
Tetrodotoxin is the most poisonous non-protein substance known to biologists and similar to that found in pufferfish. It blocks the conduction of nerve signals to muscles causing blood vessels to relax and leading to a sudden drop in blood pressure and then shock. In a nutshell, the toxin blocks the signals from your brain that tell your heart to beat and lungs to breath.
When approached or attacked by a predator, efts may assume the Unken reflex, a defense posture taken by many amphibians to show off the aposematic skin. The eft flexes its mid-section making the head and tail raised and curled over the back in the shape of a horseshoe.
Efts are about ten times more toxic than the aquatic adults. Just a small amount has been shown to kill mice in a mere 10 minutes, but both forms will kill mice if eaten in high enough concentrations. Blue Jays outright reject them as food. Efts swallowed by toads or snakes have been regurgitated after 30 minutes and recovered rapidly without lasting ill effects. But not all predators are deterred. Raccoons can apparently eat efts without any apparent toxic effects.
A few years ago a friend was watching a mallard on her pond when suddenly the duck shuddered, and died. I performed a quick necropsy to see what it might have in its digestive tract. What I found surprised me, dozens of partially digested Eastern Newts. I will never know for sure what killed the duck, but I sure was suspicious it chose the wrong meal.
No matter how hungry you are on your hike, whatever you do, don’t eat the newts.