Eft Up! The Magnetic life of the Red-Spotted Newt

By Daniel Manget

The Red Eft stage of Notophthalmus viridescens, Taken by Daniel Manget

The Red Eft stage of Notophthalmus viridescens, Taken by Daniel Manget

It’s the most common Salamander in North America but the only Newt east of the Mississippi.  It has to be one of the most charismatic and intriguing creatures in North America.  It has 4 stages of life, can live for 12 to 15 years, has the same toxins as a poison dart frog, a homing device that rivals the Pacific Salmon, Pheromones that are unlike any other recorded in the wild today, and possibly the answers to the future of heart repair.  All this in the Red-Spotted Newt, Notophthalmus viridescens viridescens, also known as simply the Eastern Newt.

 

A Newt is a type of Salamander that spends a stage of it’s life cycle on land and another in water.  So all Newts are Salamanders but all Salamanders are not Newts.  This charismatic creature has gills during it’s aquatic larval stage, loses it’s gills and grows lungs so that it can wander off into the woods to explore.  When marching around in the woods it is called a Red Eft and can wander for up to 7 years before regrowing it’s gills and returning to the pond to finish it’s unique life.

 

During the Eft stage of life, the Newt turns a bright orange to show predators that it is highly toxic and to eat the cute little guy at it’s own peril.  The skin of the Newt during the adult and Eft stage contains a chemical called Tetrodotoxin which is the same type of toxin contained in the skin of the Poison Dart Frog, the Puffer Fish, and the Blue-ringed Octopus.  Where this toxin is derived from is still a mystery but scientists know that it is accumulated from something in the environment; probably a specific type of bacteria consumed.  Research has shown that the levels of toxins can vary widely between individuals and the four subspecies of Eastern Newt and have even been absent in Newts found in Florida and Nova Scotia. Some research has shown that the toxins in the skin on the back of the Newt to be much stronger than on it’s underside and can kill a mouse or a trout within 5 minutes after being ingested.  The Rough-skinned Newt, Taricha granulosa, is one of the most poisonous animals known to science having killed multiple humans in past incidences.

 

Salamanders frequently use pheromones to communicate to other potential mates but the Red Spotted Newt has used them in ways not seen in vertebrates before.  There is a male to female ratio of almost 3 to 1 (poor guys) so competition for the ladies is intense making the guys have to get really creative if they want to pass on their genes.  What they came up with is the first known male repellent pheromone.  A male  Eastern Newt can tell another male to “back off, this is my woman” all through a chemical signal.  Actually, a female courting Newt will send out her pheromone advertising her readiness to mate and whichever male can sense her scent first can send out his repellent pheromone to make her scent less attractive to other possible mates.  A move desired by many single humans.  This technique is thought to be used more commonly in the insect world.

Adult Stage taken by Brian Gratwicke

Adult Stage Eastern Newt taken by Brian Gratwicke

 

 

For various reasons, the Eastern Newt has to migrate away from it’s home pond.  It does this during it’s juvenile Red Eft stage, when winter is approaching and their pond will freeze through, or during drought in order to survive an evaporating pond.  After it’s ramblings, the Newt will usually return to it’s home pond to breed and has some amazing and sophisticated ways of doing so.  First, it can directly recognize the sight and smell of “home-sweet-home” that is ingrained in it’s body.  Research has showed that the Newt also has the ability to use a “Map and Compass” approach never recorded before in amphibians.  It uses the patterns of light coming from the sun, even when it is cloudy, to orient itself to its location.  The compass it uses is literally in its blood.  Red-Spotted Newts are the first amphibians believed to have a Ferromagnetic biomineral inside it’s body to help it read the electromagnetic field of the planet.  The material itself has not been described in full but experiments show magnetic material (such as Magnetite) is highly likely to be the answer to the incredible homing capabilities of N. viridescens.  

 

The last remarkable characteristic of the Eastern Newt is one followed closely by the medical community.  The Newt is a model organism for body part regeneration.  Most of us know that when catching a salamander or lizard, it will lose it’s tail if that’s the only thing you grab a hold of but, this creature takes that to a whole new level.  N. viridescens “has tissue-engineering skills that far surpass the most advanced biotechnology labs. The newt can regenerate lost tissue, including heart muscle, components of its central nervous system and even the lens of its eye” (Cormier, 2013, Nature).  This Newt is so revolutionary in the way that it regrows it’s body parts that a team of scientists are mapping it’s entire genome in order to discover the secrets behind it’s unrivaled capabilities.  The problem, however, is that it’s genome is 10 times as large as the human genome and is therefore proving to be more difficult and take much longer than anticipated.

 

Borland, S. Chris (1998), “Use of a Specialized Magnetoreception System for Homing by the eastern red-spotted newt Notophthalmus viridescens, Journal of Experimental Biology 188 (1): 275–291

Brassart, J.Kirschvink, L., Phillips, J., and Borland S. (1999) “Ferromagnetic Material in the Eastern Red-spotted Newt Notophthalmus viridescensJournal of Expirimental Biology 202(22):3155-3160

Daesik ParklHeather L. EisthenCatherine R. Propper. The pheromonal repelling response in red-spotted newts (Notophthalmus viridescens). Chemical Signals in Vertebrates 102005, pp 42-48

Tattersall GJ1, Tyson TM, Lenchyshyn JR, Carlone RL. Temperature preference during forelimb regeneration in the red-spotted newt Notophthalmus viridescens. J Exp Zool A Ecol Genet Physiol. 2012 Apr;317(4):248-58. doi: 10.1002/jez.1719.

Wheeler, W.M., Julian F. Watkins II. The American Midland Naturalist, The University of Notre Dame. Vol. 80, No. 1, Jul., 1968

 

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