Mazama Newt toxicity

Mazama and Oregon Newt
Mazama Newt from Crater Lake (left) and Rough-skinned Newt collected outside the park at Spruce Lake (right).


Both the Mazama Newt, and the more widely distributed rough-skinned newt, produce toxins as a defense against predation.

  • Newts are the only land animal to contain tetrodotoxin (TTX), an incredibly potent neurotoxin. Tetrodotoxin is also found in the deadly puffer fish and blue-ringed octopus.
  • Some newts can produce enough toxin to kill 17 humans.
  • Rough-skinned Newts from low elevations have 4000 times the toxin as Mazama Newts in Crater Lake.
  • The Mazama Newts found in Crater Lake are not very toxic compared to Oregon newts outside the lake.
newt toxicity bar graph
Toxicity levels for newts from four locations in the state of Oregon, USA.  Longer bars indicated higher toxicity levels.  Crater Lake newts are not very toxic compared to newts found in Soap Creek.


Why are the Mazama Newts not very poisonous?

Mazama Newts found their way to Crater Lake as early as 6000 years ago when there were no fish or crayfish predators. It takes valuable energy for the newts to produce the toxin and food resources for the newts in Crater Lake are scarce. The Mazama Newt may have lost its' toxicity due to the lack of predation and the general scarcity of food in Crater Lake .

Last updated: March 18, 2016

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