Killer Newts of the West Coast

I was six-years-old in 1955 when my parents took the family to Holy Jim’s Canyon, in Southern California. In those days it was a relatively wild place with a little creek quietly bubbling through the rocks and into several pools. I recall seeing what I thought were, long thin reddish-brown and orange fish swimming in the pools.

I caught one with a net and discovered it had little arms and legs. It was a kind of salamander called a California newt. I remember holding the newt in my hands and marveling at its tiny hands and feet. Little did I know, and don't tell my mother, I was handling an animal that produces the most potent poison on the planet.

On the ninth of July 1979, a 29-year-old man acted on a dare from his drinking buddies by swallowing an eight-inch long salamander. He didn't know it at the time, but it would be his last meal. This particular salamander was a rough-skinned newt, one of four highly toxic newts that live on the west coast of North America. All four newts are of the genus Taricha (T. granulosa or rough-skinned newt; T. rivularis or red-bellied newt; T. torosa or California newt; and T. sierrae or Sierra newt).

Within minutes the drunken man's lips began to tingle, and over the next two hours, he complained of numbness and weakness throughout his body. He said he thought he was going to die yet refused to go to the hospital. Then, left alone for fifteen minutes, he ceased breathing. Resuscitation measures failed to revive him, and he died.

All west coast newts in the genus Taricha contain enough neurotoxin to kill a human being - in some cases dozens. As a child, I handled them without any adverse effect. The poison in its skin must be swallowed to cause harm, although it's a good idea to wash your hands thoroughly after handling a newt. This neurotoxin, called tetrodotoxin, is the same as the poison in fugu (or puffer fish) notorious for killing sushi aficionados. Tetrodotoxin is a thousand times more toxic than cyanide.

Tetrodotoxin blocks nerve signals to the muscles, ultimately causing the victim's breathing and heart to stop. One study found that the skin of one rough-skinned newt contained enough tetrodotoxin to kill 25,000 mice. Another study found that only 25 milligrams would kill a person weighing 170 pounds. No known antidote exists.

The mystery is why these little creatures would need to be so toxic? The color of their bright yellow, orange, or red belly warns would-be predators that they are poisonous. The acrid odor of newt's tetrodotoxin wards off most other animals. There is one animal that does eat these deadly newts - the common garter snake (Thamnophis sirtalis). The fascinating story of the interactions between these two species will be the subject of the next blog, due to come out on the 20th of February.