Tuesday, September 25, 2012

Eastern Red-backed Salamander

During my recent camping trip, I spent nearly a week on our acreage that has a trout stream running through it before moving to my regular lakeside site. "The land" (we're creative) is a fabulous spot for exploring - I never know what I'm going to find.

While cleaning pine needles out of the dogs' water dish one morning, I went to pick up a twig and realized it was alive. With a red stripe:


This very cute critter is an Eastern Red-backed Salamander (Plethodon cinereus). One of just six salamanders found in Minnesota.

It has some fascinating qualities:
 - it's the only Minnesota salamander to not go through an aquatic life phase. It spends its life entirely on land (I felt very sorry for it being trapped in 2" of water for who knows how long after learning this).
 - it's a lungless variety of salamander (largest salamander family). It gets all its oxygen through mucous membrane and skin gaseous exchange (now I felt doubly-bad - they must be able to go without oxygen for awhile!)

It's also one of our smallest salamanders, measuring in at a max of 5."

When the young are born, they look exactly like the adults, just teensier: only 1" long! They do not go through a metamorphsis.

Speaking of being born: Eastern Red-backed Salamander sex is occurring right now, and will continue into the early winter months. Even though they mate now, the female won't lay her eggs in a damp hollow log or a rock crevice until next spring. The clutch size is amazingly small: 15 or fewer eggs, average size is 8. And she only reproduces every other year.

But, she's a great mom! Once she lays her eggs she'll curl up around them and guard them for the two months it takes the eggs to hatch. Of course, a few weeks after they hatch they're entirely on their own - but at least she protects the eggs and gives them a good start on life.

And, she remembers her offspring. Eastern Red-backeds mark their territory through scent glands. In times of drought, when food sources are scare, the female will allow offspring back into her territory to hunt until the scarcity eases. Just her offspring, others are chased off. That's pretty neat.

Their diet is all sorts of invertabrates, including spiders, mites, worms, beetles, snails and even ants.

Logging has a very negative impact on these terrestrial amphibians and even fragmentation of forests can affect their population. Some research has found that it can take 40-60 years for their population to rebound in areas of heavy logging. They do best in undisturbed deciduous forests or mixed conifer forests (which is what our land is) with plenty of woodsy material on the forest floor.

During winter, they'll burrow down and enter a state of torpor, they do not actually hibernate. In fact, some references cited seeing them above ground and active on mild winter days. Unlike many of our tree frogs, Eastern Red-backeds can't survive freezing, so scientists believe they remain somewhat active underground during the winter. Discovery of full stomachs found in winter samples also points to the fact that the salamanders will awaken and feed, moving around as needed.

There are two other forms of the Eastern Red-backed Salamander: The red phase (crythristic) and the gray phase (leadback).

Challenge: Do you like looking for worms after an evening rain? If you live in Minnesota keep your eyes open for the gray-backed form. It's never been documented in the state! (Amphibians and Reptiles of Minnesota, Barney Oldfield and John Moriarity) *note that in the book they also list the red phase as having not been documented, but it since has been. A new update of the book will be available a year from now.


Citings:
http://amphibiaweb.org/cgi/amphib_query?where-genus=Plethodon&where-species=cinereus
Amphibians and Reptiles of Minnesota
Grizzly Run



4 comments:

  1. What a wonderful and informative post! I adore Salamanders and this one is a beauty.

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  2. I like salamanders too, and there's a world out there. I hope to also post amphibians too one day. They have great skins and colors.

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    1. I bet you have all sorts of cool amphibians by you, Maria. Can't wait to see what you do with them!

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