A stocky newt with rounded snout, it ranges from light brown to olive or brownish-black on top, with the underside, including the head, legs, and tail, a contrasting orange to yellow.

[3] They are similar to the California newt (Taricha torosa) but differ in having smaller eyes, yellow irises, V-shaped tooth patterns, and uniformly dark eyelids.

[2] Males can be distinguished from females during breeding season by large swollen vent lobes[3] and cornified toe pads.

They are uncommon east of the Cascade Mountains, though occasionally are found (and considered exotic, and possibly artificially introduced) as far as Montana.

[6] Toxicity is generally experienced only if the newt is ingested, although some individuals have been reported to experience skin irritation after dermal contact, particularly if the eyes are touched after handling the animal without washing hands.

[8] This toxin targets voltage-gated sodium channels via binding to distinct but allosterically coupled sites.

Increases in the amount of newt then apply a selective pressure favoring snakes with mutations conferring even greater resistance.

[6] There has been phylogenetic evidence that indicates elevated resistance to TTX has originated independently and only in certain species of garter snakes.

As a result of tissue exposure to the toxin, newts have evolved a protection mechanism via a single amino acid substitution to the voltage-gated sodium channel normally affected by TTX.

Puffer fishes show a similar amino acid sequence that allows them to survive from their own toxin exposure.

[14] Parasites include the trematode Halipegus occidualis, the adult form of which may infest the newt's esophagus and the anterior of its stomach.