Sunday, January 21, 2018

Beware The Mighty Rough Skinned Newt.

On a winter's day take a walk in the woods along the north coast. You might accidentally step on a rough skinned newt (Taricha granulosa Skilton) as they are camouflaged by fallen leaves on the forest floor They are encountered most often in rainy or cloudy weather.

The newt has a rounded snout and its color ranges from light brown to brownish black or olive on top. The entire underside of the newt is orange to yellow. The skin is rough except for the males during mating season. Their size is 6 to 9 cm snout to vent. Their overall length is 11 to 18 cm. They have smaller eyes than the California newt (Taricha torosa) and their irises are yellow. The rough skinned newt has V-shaped tooth patterns and dark eyelids. During breeding season the males have large swollen vent lobes and cornified toe pads.

Their habitat range extends from Santa Cruz, California to Alaska and they are uncommon east of the Cascades. One colony can be found in ponds north of Moscow , Idaho. But it is believed they were introduced there.

If you see one of the cute little buggers DON'T pick it up! Their defence mechanism is the toxin they produce from the skin glands. This toxin acts a warning to predators. Generally a human must ingest a newt to be affected by its toxin. But it has been reported that some persons have suffered skin irritation if touched. The eyes are especially vulnerable if touched after handling a newt without washing hands. A person died after eating a newt in 1979..

The toxin that is produced by the rough skinned newt is called tetrodotoxin (TTX). It is also found in puffer fish a a few other marine animals. The toxin has the effect of inducing paralysis by blocking the electrical signals needed for conducting nerve impulses. This has the effect of inducing death by asphyxiation.

The only creature that has been able to resist the venom of the rough skinned newt is the common garter snake. The garter snake's resistance is made possible by its ability to gauge the amount of toxin in the the newt. They do this by partially swallowing the newt first. The garter snake is the only known animal that can survive eating a rough skinned newt.

The newt has only a heightened resistance to their own toxin. They inject themselves with a bit of toxin each time they release some. Thus they have evolved a protection mechanism against their own toxin.

This war between the garter snake and the rough skinned newt is interesting. The snake releases a chemical signature after it eats a newt. This is detected by a nearby newt and it triggers an avoidance response. This allows the newt to differentiate whether a snake is resistant or sensitive to the toxin.

Folklore has it that some Indian tribes used ground up newt to poison their political enemies. Members of the genus Taricha from the Pacific Northwest are believed to be by far the most potent. The toxin exhibits a foul smell and will appear in a milky foam on the surface of the skin.

The poisonous effect of the newt is only through the digestive tract, a break in the skin or via mucous membrane such as the eyes. That being said, it is safe to handle a newt if you wash your hands thoroughly afterwards.