The Carlisle Mosquito Online

Friday, March 21, 2008


Spotted Salamander


(Photo by Kay Fairweather)

We need a calendar to tell us it’s spring about as much as we need an economist to tell us we’re heading into a financial winter. I think of spring as a period of rational exuberance – at least in the world of nature. We see the signs and feel the changes. One of the many signs is the salamander migration.

Name. The spotted salamander is Ambystoma maculata where Ambystoma comes from the Greek words

When and where seen. I found this spotted salamander sitting on the leaf litter in one of my basement window wells on March 14. It could have been trapped there for some time. They are not normally out during daylight hours. This one was probably ailing. It had a skin tear and was quite lethargic. I placed it under some leaf litter in another part of the yard, near some old logs and soft soil. It may have recovered. It is gone from where I left it.

This egg mass of a spotted salamander is enclosed in jelly and attached to a twig. (Photo by Kay Fairweather)

There is nothing else quite like the spotted salamander. The body is black and it has an irregular row of large bright yellow spots on each side of the body starting behind the eye and running right down the tail. The legs also have yellow spots. The salamander gets to be about eight inches long overall including the tail. This one was around seven inches.

Life cycle. Spotted salamanders are completely dependent on vernal pools for breeding. In early spring, on a rainy night when the temperature is 40 degrees or more, they migrate en masse to vernal pools to mate and lay eggs. They usually return to the pool they were born in. The eggs hatch within eight weeks into legless larvae with external gills and a pair of temporary “limbs” that are used as stabilizers to keep them upright. Vernal pools eliminate the risk of predation by fish but it’s still not a rose garden. The larvae are eaten by carniverous insects (like the predaceous diving beetle), other salamander larvae, and turtles. Thesurvivors trade in their external gills for legs. This process accelerates as the vernal pool dries and in a typical season the salamander will be ready for life as a land-dwelling animal before the pool has gone. It will then live in the soil under logs or in mammal burrows on a diet of various invertebrates including worms, spiders, centipedes and snails – in a wooded location within a half mile or so of the pool.

Eggs. The life style of the spotted salamander means they are not often seen. The eggs on the other hand are relatively easy to see in clumps in sunny areas near the surface of the pool attached to twigs or other vegetation. A single clump can contain up to 250 eggs all enclosed in a firm clear jelly which can protect the embryos from short-term fluctuations of water levels in the spring. The same pool may also contain wood frog egg masses since the wood frog is similarly dependent on vernal pools for its life cycle. Wood frog egg masses are easily recognized. They may have up to 1,500 eggs in a single clump and there are often many clumps in the same location. The eggs are smaller than those of the spotted salamander and are not enclosed in a matrix of jelly.

Vernal pool certification. The spotted salamander (and the wood frog) are species whose presence is used to certify a vernal pool. The egg masses are the necessary evidence of the species.

References. Roger Conant, Peterson Field Guide to Reptiles and Amphibians; Leo P. Kenney and Matthew R. Burne, Field Guide to the Animals of Vernal Pools – an excellent book for children or adults. It has lots of color photos and excellent descriptions.∆

© 2008 The Carlisle Mosquito