Wednesday, March 05, 2008

Secret Nights of Salamanders

Perhaps you can ignore the first time a salamander knocks on your door, but when it happens again, it’s time to pay attention. This soggy summer of ours has brought renewed encounters with Colorado’s only species, the tiger salamander (Ambystoma tigrinum). I hadn’t seen a wild one in six years, which says something either about our weather, or the nonexistent night life I’ve been leading! One night when my husband found one at the door about 2 a.m., I recalled my first encounters with these startling but delightful critters. I’ve also noticed lately that many people who have never met them are surprised to discover them here at all, and wonder what—and why— on Earth they are. The days may be ours, but the nights belong to them.

Field work in eastern Wyoming brought me my first encounters with tigers. After a day or more of good hard rain, suddenly our campsite was crawling with these large amphibians. Groping a damp tent floor in the dark to make sure none of them are planning on spending the night with you is not a great way to develop fond feelings for the slimy fellows, but it does get you wondering about their enigmatic lifestyle. Where, in a ten-thousand acre expanse of sagebrush (and little else), does a tiger salamander come from?

We think of the prairie as a dry place, albeit interrupted by stream channels or swales that are also usually dry. The evidence of water is there in the paths it has taken or the places it has rested, but it is rarely visible. The monsoon season we had this summer changed all that. At the Plains Conservation Center, a large preserve on the prairie east of Denver, water was everywhere. In pools and puddles, flowing down those abandoned-looking channels, and even filling the buffalo wallows. I imagine that, by now, amphibians too are everywhere, and not just on the prairie.

Taking advantage of all this moisture, adult salamanders leave the burrows where they’ve been hiding from our typical summer sun, and wander about, especially at night. Young salamanders, newly metamorphosed, are also on the move. Perhaps the rain, to salamanders, signals greener pastures or happier hunting for food or mates. Salamanders start life as eggs, then larvae, in ponds and pools in every county in Colorado. In dank muddy prairie potholes and cool subalpine ponds, they hatch and feed with their fellows. The larvae, with three gills on each side of their necks, are creatures who must live strictly in water. As they grow into adults, the gills are lost, and they venture out on land. Sometimes drying ponds push them into maturity a little early— the ones I saw this summer seemed very small for adult salamanders.

They were especially small compared to the growing monsters who live at the local Natural History Museum, where we have been impressed with the engaging personalities and voracious appetites of these easy-going amphibians. Alert and responsive, especially if there’s food in the offing, they are favorites of staff and visitors alike. Most visitors. One mentioned that, had she known such creatures prowled her backyard, she would have moved! It’s true they’re a bit slimy and strange looking, but they have cute faces, and you do grow to like them once you get to know them.

The sliminess we correctly associate with amphibians is part of their defense. The mucus layer over their skin contains antibiotics that help them resist infection. Like reptiles, amphibians also shed their skins as they grow. Instead of dry papery skins like snakes, though, they shed a diaphanous membrane, which they often eat. No sense wasting good protein. Sometimes I’ll see a ghostly hand floating in the tank, evidence of a recent shed, inside-out like a discarded glove. Because they spend so much of their lives in water, their skin is in constant contact with whatever the water brings, including some of the oxygen they need. Here salamanders, mythical creatures associated with fire, are truly playing with fire, as many of our waters bring pollutants that are also in direct contact with that critical layer of skin. Tiger salamander populations seem to have remained strong as other amphibians have begun to decline, but in recent years this may be changing, and some researchers are looking more closely.

Local populations of salamanders become adapted to specific conditions of their home areas, and that’s important in a species that occurs in such a wide variety of habitats and deals with drastically different conditions across its range. In fact, biologists warn us that some amphibians become so closely tied to their habitats that attempts to re-establish dwindling populations through captive breeding and release programs can hurt rather than help. Our one species is the only salamander in the entire state, but it has developed three locally distinct subspecies, each with a different color pattern. As a result of transport and release by fisherman, the original distribution has already become almost hopelessly mixed.

Although I normally wouldn’t recommend wild animals as pets, tiger salamander larvae are readily available under redeeming circumstances. Instead of capturing wild ones, you might consider liberating one or two from a bait shop. If you decide to put a tiger in your tank, be aware that you’re taking on a long-term commitment; these guys can live 20 years or more. Observing amphibians in captivity or in the wild can teach us a lot about the lives of these amazing animals who share our neighborhoods and wild places so secretively that most of us remain unaware of their presence.

Copyright, S.L. White, 2008. Illustration copyright Jan Ratcliffe.
Originally published in Upbeat, September 1997.


nina said...

I like!
Especially the tiger in your tank wording.

Since starting into my vernal adventure I've discovered how much I DON'T know about salamanders--your story contains much helpful info.

I wish I could take you out to my pools!

Instead I'm relying on my camera to capture images, then ferreting facts from texts--much larger a pastime than I'd thought it would be!!

SLW said...

Thanks for coming by, Nina... I was pretty proud of this piece and I'm glad you found it useful, but I must say, your salamander stories are outstanding! Your writing is just so creative... and you're having real adventures. Keep up the great work; your blog is a treat to read.

I saw vernal pools at Flint Ridge when I was in Ohio last summer-- so maybe someday I'll see your study site. One never knows, eh? I still can't believe you're in spring already, peepers and all-- we got 6 inches of snow today!