DIVERSE SALAMANDER LIFESTYLES

     Frogs, toads and salamanders are invertebrate-eating amphibians.  And smooth-skinned frogs and salamanders must keep their thin skins moist to survive.  But toads' bumpy skins retain water, allowing them to be more independent of water, except to spawn. 

     Several kinds of salamanders live in southeastern Pennsylvania, each in its own habitat and lifestyle.  And three species of them demonstrate those lifestyles.

     Spotted salamanders start life with gills and swimming tails in woodland pools and puddles.  They feed on algae and rotting vegetation and develop lungs within a few months.  Then they emerge from the water and spend the rest of their lives under moist carpets of fallen leaves in woods, where they consume invertebrates.  These beautiful, black and yellow-spotted salamanders only return to water, as adults early in spring to spawn, creating exciting little groups of themselves in pools and puddles.         

     Eastern newts start life in ponds, where they feed on aquatic invertebrates.  They, too, grow lungs, leave the water and live under damp, fallen logs and foliage on forest floors as red efts, because they are mostly, strikingly red.  

     But after a few years as red efts on land, these newts return to ponds to live the rest of their lives, but come to the surface to gulp air.  As adults, these lovely newts are olive on top with two rows of red spots down their backs and yellow underneath, sprinkled with black dots.  And females of the species deposit eggs on water plants in the ponds they call home.  

     Eastern newts probably once followed the amphibian lifestyle of starting life in water, but emigrating to land, only going to water to spawn.  But maybe they couldn't compete with their salamander relatives for space and food on woodland floors, so a population of them returned to water, where there might have been less competition, to live as adults, and stayed their ever since, except for the red eft stage in their lives.  And there adult newts are to this day.  

     The red efts that stayed on land all their lives died out.  Only efts that returned to water as adults survived.     

     Red-backed salamanders developed a lifestyle that has no aquatic stage.  Maybe a population of them couldn't get to water to spawn, so each female deposited her cluster of  gelatin-like eggs in damp, dark places under rocks, and fallen leaves and logs on woodland floors.  The eggs remained moist enough to allow the survival of the embryos that hatched as tiny editions of their parents, complete with legs and tails, on forest floors.  These salamanders are independent of standing water to spawn.    

     But red-backs have no lungs.  They exchange gases through their thin, moist skins.  

     Today red-backs' range is across much of the eastern United States, and they are an abundant species in scattered colonies in isolated woodlots.  New species of salamanders probably are developing in those remnant, scattered woods, surrounded by cropland where red-backs can't live.  Therefore, there is no exchange of genes among salamanders living in isolated woods, making conditions for the development of new species.  

     Some kinds of salamanders are intriguing creatures that developed different ways to survive in a variety of habitats.  They have evolved to live in niches free of competition from their relatives.        

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