As February comes to an end, we approach the season of the ephemeral “Salamander Rains.” When soil temperatures begin to warm, spotted salamanders (Ambystoma maculatum), which have spent the winter in underground burrows, are alerted to the change in season. Late winter is their time to breed. But they will not begin their migration to their breeding vernal pools until the first warm rains soak the ground and evening air temperatures reach 40 degrees Fahrenheit. This is the signal to spotted salamanders, as well as to interested naturalists, to get a move on.
Spotted salamanders migrate en masse on these rainy nights to the vernal pools where they were born. They enter the water to mate and lay eggs before heading back to their terrestrial life. Spotted salamanders are dependent upon these pools for their species’ survival. When a breeding pool is filled with soil, or the trees surrounding it are cut down, or stormwater is directed into the wetland, a population’s breeding site is destroyed. Likewise, if the uplands around a breeding pool are developed, the adults no longer have a place to live.
Glossy black with bright yellow polka dots, adult spotted salamanders are extraordinary creatures. They can grow to be 8-9 inches long and live at least ten years. They live most of the year hidden among the moist leaf litter and woody debris on the forest floor, feeding on earthworms, snails, various beetles, spiders, and other woodland invertebrates. The short period of migration and breeding is the optimum time to observe these elusive amphibians. Later, the larval young, which hatch from a globular egg mass deposited by the adult female in the breeding pool, can be seen swimming in the shallows. They will live for a few months as aquatic creatures with external, feathery gills. Salamander larvae are voracious underwater predators that feed on anything that moves, including mosquito larvae.
There are those among us who find these salamanders fascinating and rather endearing. You might see us out walking the roads on these rainy, late winter evenings in rain gear and boots, flash lights aimed at the pavement. We are there to observe the migration, and to lend a helping hand by carrying salamanders across the road in the direction they are heading. (Roads bisecting their migration routes are one of the main causes of adult salamander mortality, since so many salamanders are run over by motor vehicles. Additionally, typical street curbing often steers the hapless creatures into catch basins where they perish. Cape Cod curbing, with its gently sloping surface, is a preferred curbing design and allows these amphibians to continue their journey to and from their breeding pool.)
Haven’t yet seen a polka-dotted salamander? Scout out a vernal pool, grab a flashlight, put on your galoshes and reflective rain gear on the first warm, rainy evenings, and get out there. And watch out for motor vehicle traffic – it always seems to travel much more quickly than it should on a rainy night.