Ambystoma maculatum, the spotted salamander, is an elusive amphibian that ranges from 7 to 9 inches in length with females being larger than males. Its colors are a striking contrast of yellow or orange spots in two irregular rows from head to tail, against a background skin color of dark brown, gray, gray-blue, bluish-black or black. Its skin also has a shiny, glossy appearance. In comparison to other salamanders it is a stocky amphibian with a thick body and rounded head. The sides of its head flare out at the jawline.
Spotted salamanders are native to North America and can be found in the southern portion of Canada from Nova Scotia to the Gaspé Peninsula. They’re also located in the eastern portion of the United States, from the north shores of Lake Michigan through southern Georgia and to the eastern parts of Texas and Iowa. In 2001, surveyors with the Minnesota Biological Survey made an unexpected discovery of spotted salamander eggs and kept them in an aquarium until the eggs hatched and they could confirm their findings. Spotted salamanders had never been recorded in Minnesota prior to that encounter. Like most salamanders, the spotted variety relies on wetlands and low-lying moist forest lands to survive. They are extremely sensitive to increases in the acidity of the water in their habitats.
Spotted salamanders living in the south are ready to breed approximately two to three years after hatching; the northern salamanders often aren’t ready until they are 5 to 7 years old. Males reach sexual maturation before females. Male spotted salamanders migrate annually to breeding ponds at night during the first rain of spring, after the winter snow thaws and before the females. Animal Diversity Web attributes the males’ early arrival to their faster movement and heightened sensitivity to rain. Once mating begins, females lay two to four gelatinous masses containing 75 to 100 eggs each. Males create up to 80 spermatophores, which are globules of sperm, and may cover competitor’s spermatophores with their own. The female takes spermatophores from several males into her body to fertilize her eggs before she attaches the egg masses to submerged plants or twigs.
Hatchlings emerge from the egg masses as larvae in four to seven weeks. They remain in the pool for two to four months. Then their tadpole-like tails become thicker and the feather-like external gills fall off as they enter the juvenile stage and can leave the pond. More than 90 percent of spotted salamanders die before reaching the juvenile stage. They either succumb to disease or predators, or the pool dries up. If they are successful in transforming to juveniles, their chances of survival are good. In the wild, most spotted salamanders will live up to 25 years, and some have been recorded as living as long as 30 years.
Larval spotted salamanders have "balancers" near their gills, which sets them apart from other species of salamanders; the balancers act like the kickstand on a bicycle and disappear after a few days. The larvae hide under debris at the bottom of the pond when they sense predators nearby. Adults rarely move unless they are looking for food or damp underground homes. They are carnivores and will if necessary eat other spotted salamanders. The bright spots serve to warn predators that their backs and tails secrete a milky toxin.
- National Geographic: Spotted Salamander
- Animal Diversity Web: Ambystoma maculatum: Spotted Salamander
- Utah’s Hogle Zoo: Spotted Salamander
- Minnesota Department of Natural Resources: Finding Spotted Salamanders (Ambystoma Maculatum) in Minnesota
- BioKIDS: Spotted Salamander: Ambystoma maculatum
- San Diego Zoo: Amphibians: Salamander & Newt
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