salamander

"Nature Guide Journal"

27 April 2002

For some reason, a salamander followed my dog into the house late the other night. Apparently it was under the edge of the door when I opened it.

I snatched it up quickly to keep it from disappearing under the washing machine, but it writhed so violently I had trouble keeping it in my hand. The dark, slick wriggler was about five-and-a-half inches long, with delicate legs and a glistening, bright-tan, ragged stripe down the back and most of the tail.

The characteristics of the stripe were the clues that my unexpected guest was a Dunn's salamander (Plethodon dunni), one of several species native to our region.

The Oregon Coast is home to nearly a dozen species of salamanders—about twice as many kinds of salamanders as frogs. Like their fellow amphibians, salamanders are thin-skinned vertebrates that lay shell-less eggs in water or water-saturated environments.

Unlike frogs, salamanders are quite elongate, retain their tails through adulthood, have front and back legs of similar size, and are born carnivores. (Most frog tadpoles are herbivores.)

Shy and nocturnal, Dunn's salamander is associated with damp terrestrial—sometimes even rocky—habitats. All salamanders need dampness, and most damp habitats in western Oregon can harbor hidden salamanders of one kind or another.

Dunn's salamander is one of our fully terrestrial woodland salamanders. Woodland salamanders spend their whole lives in wet, damp environments, such as in rotting logs or between damp cobbles, but don't spend time submerged in water—not even as eggs or larvae. All fully terrestrial salamanders in the Pacific Northwest are lung-less, taking in oxygen only through their damp skin and the lining of their mouths.

Aquatic salamanders, such as the rough-skinned newt (Taricha granulosa, sometimes called a "water dog"), lay their eggs in water and may spend much or all of their lives submerged. Some aquatic salamander hatchlings look like skinny tadpoles with legs that emerge later; all aquatic salamander hatchlings have external gills that later give way to sac-like lungs. Occasionally, some aquatic salamanders retain their gills and remain aquatic as adults. (Such individuals are called "neotenic.")

As with most other terrestrial salamanders, Dunn's salamander females give maternal care: curled around her small clutch of eggs, her skin's mucus secretions keep the developing eggs moist and fungi-free. Terrestrial salamanders are further along in development at hatching than the aquatic salamanders, and the young emerge from the egg looking like miniature adults.

The skin secretions of salamanders is at least unpalatable to most potential predators. The secretions of some salamanders, most notably the rough-skinned newt, is quite poisonous. Those toxins are the reason it's a good idea to wash your hands after handling a salamander. If you pick up a salamander, be very gentle; clean, wet hands are best.

While few predators will eat a salamander, salamanders will devour just about any prey of the right size: small invertebrates such as insects, worms, mites, woodlice, and small slugs and snails.

I let my squirming visitor go after a brief inspection. Nice to know such an interesting resident finds my yard welcome habitat. I wonder how many more enterprising wrigglers are secretly stalking outside?

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