ENHS Nature Trails December 2000 Article 3

Salamanders

One of the things I love about herpetology in the Pacific Northwest is that there is very little "down time." Throughout the year there are animals to observe, though the cast of characters changes seasonally. This is in contrast to most of the United States which experiences a more continental weather pattern. That's a scientific way of saying that for most of the winter it's too cold for brass monkeys, and amphibians and reptiles deal with the cold weather in the only sensible way--they sleep it out. When the rains arrive in Western Oregon, several amphibian species that were waiting out the summer drought in a deep, damp hole, become active closer to the surface. This is especially true in the coastal mountains where heavy winter rainfall and the temperature-moderating influence of the Pacific Ocean coalesce into prime time for serious salamander sleuths.

The Roughskin Newt (Taricha granulosa) is brown with orange and sports an orange belly. It is the most commonly encountered salamander in Oregon because adults are found out and about during daylight hours; most salamanders restrict their surface activity to night-time. Roughskin newts are named for the small bumps on their brown skin. These are actually clusters of poison glands containing a substance called tetrodotoxin which attacks the nervous system. Although a single adult newt is thought to contain enough tetrodotoxin to kill 2.5 adult humans (I've always wondered where you would find half an adult human that could still be killed), these newts are harmless provided that you skin them before you eat them. My pet hypothesis as to why roughskin newts can be found on the surface during daylight hours: With skin like that, why worry!

Roughskin Newt (Taricha granulosa)

Small seeps and springs harbor a variety of species. This is the only acceptable habitat for the Southern Torrent Salamander (Rhyacotriton variegatus). These small salamanders rarely exceed four inches in total length. Adults have large eyes, a low tail fin, a light brown back and a light yellow belly with black spots on the back and belly and white spots on the sides. Larvae are similarly colored but have small gills and a flattened head with smaller eyes. Look for both larvae and adults under objects where the ground is saturated but water is not flowing. Torrent salamanders are listed as a sensitive species in Oregon, largely because logging exposes seeps to direct sunlight and raises the water temperature above their narrow range of tolerance.

Dunn's Salamander (Plethodon dunni) is also found in and around seeps but occurs on the forest floor during the wettest months of winter. Adults are four to six inches in total length, have no tail fin, display a greenish stripe with uneven edges on the back and tail, and have a gray belly with light spots. You won't find larvae because Dunn's Salamander exhibits direct development. Eggs hatch into juvenile salamanders with no aquatic larval stage. They belong to a large family containing over 200 species that have no lungs, appropriately named the Lungless Salamanders. Oxygen is taken up entirely across the skin and the lining of the mouth, and the muscles and parts of the skeleton that once were used for both feeding and breathing have evolved into very sophisticated (at least for salamanders) feeding structures.

The Western Redback Salamander (Plethodon vehiculum) is the closest living relative of Dunn's Salamander and has all of the curious lungless salamander attributes. Western Redback Salamanders are more tolerant of dryer conditions and can be found under objects or inside decaying logs on the forest floor and only occasionally inhabit wetter seeps and springs. These salamanders are very small, and an adult over four inches in total length is huge. As their name implies, many individuals have a brick-red stripe along the back and tail. However, identification is complicated in coastal populations where individuals in the same population may have a stripe of red, green or yellow or may have no stripe at all. In the field they can usually be distinguished from Dunn's salamander by the sharp, even edge of the stripe.

Another common lungless salamander is the Oregon Ensatina (Ensatina eschscholtzii). (Yes, there really are two "sch's" in the Latin name). They are easily recognized by the constriction at the base of the tail and yellowish orange coloration on the legs where they join the body. Ensatinas seem slightly more resistant to drying than the two species of Plethodon. They are commonly found in heavily decayed logs on the forest floor but also occur inside rock and debris piles. Decayed logs are an important habitat for several salamander species in Oregon and are a vanishing resource in areas where logging removes trees long before they die and rot on the forest floor.

Oregon Esatina (Ensatina eschscholtzii)

An adult Pacific Giant Salamander is a sight to behold! It is easily the largest salamander species in Oregon, with adults growing to over a foot in total length. Adults are dark brown, usually with distinct tan or coppery marbling throughout. They can be found under logs and occasionally under smaller cover objects on the forest floor. Larvae are dark brown with a flattened head, short gills, and a low, mottled tail fin and can be found in seeps, springs and streams. In some cases the larvae do not metamorphose and become large, sexually mature, gill-breathing adults. My most vivid salamander memory is of a coastal canyon in November, where a large adult Pacific Giant Salamander was partly emerged from a burrow on a green, mossy slope next to a golden chanterelle. Unbelievable...

Because most salamanders are secretive and hidden during daylight hours, you will have to actively search for them. If you choose to search for them, and I hope that you do; remember to be a conscientious amphibian enthusiast and return both the salamander and the cover object to their original positions.

Photo Credits:
Tom Titus

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