When the glaciers melted, the two species met and interbred, resulting in the hybrids. Next door, my neighbors often find a spotted salamander during the summer when they lift a log at the edge of their garden. Spotted salamanders are gray brown to blue black with bright yellow or orange spots in two irregular rows down the length of their bodies. They migrate, sometimes as far as 420 feet, to breed in the pools where they themselves were born. They spend one or two weeks in the pool where they mate and then return to their usual haunts under leaves, rotting wood, stones or in underground burrows.
Spotted salamanders are nocturnal and hibernate in winter.
Amphibians, which include salamanders, were the first vertebrates to leave water to live on land, about 360 million years ago. Competition from the reptiles, birds, and mammals that then evolved has limited their success. Of amphibians, there are now only toads and frogs, salamanders, and caecilians, which are worm-like creatures found in the tropics. Most species of amphibians must return to water, or a very moist environment, to breed. They need moist habitats, such as underground or in wetlands, or they are active only at night, like the spotted salamander.