Post by Jen Berlinghof
It was late March, fourteen years ago, when I took my first hike at Ryerson Woods. The air felt heavy with thawing snow. The sun warmed my back for the first time in many months. Standing at the edge of a small, glistening pool of water in this oak flatwood forest, I saw my first blue-spotted salamander (Ambystoma laterale). About the length of a crayon, this inky black amphibian is adorned with tiny, blue confetti-like spots on a dewy body. Blue-spotted salamanders hide in abandoned mammal burrows or under logs most of their life. Each spring, warming temperatures and increased precipitation lure these creatures out of their covert caverns for a slow and steady march to their breeding ponds.
Blue-spotted salamanders are one of the earliest amphibians to breed in Lake County, Illinois. They mate “explosively” during the first three days of thaw, emerging en masse each evening at vernal pools, which are temporary woodland ponds created by snow melt, rain and rising water tables. Here the inhabitants are in a race against time. As soggy spring gives way to arid summer, these temporary reservoirs dry up. As treacherous as this ticking timeline may sound, its transient nature provides some advantage for defenseless creatures at the low-end of the food chain. Because these pools dry up each year, there’s no way for predators such as fish or bullfrogs to make their homes there.
At two to three years of age, this species of salamander returns to the same vernal ponds they swam in as larvae to begin their own breeding ritual as adults. Male salamanders attract females with the fancy footwork of a courtship two-step. If the dance is successful the male rubs his chin on the female’s head, transmitting pheromones between their slippery skin like a whispered love song. Following this cheek-to-cheek dance the male deposits a spermatophore (a mass containing sperm) near the female. She collects the sperm packet using her cloaca (an opening used for breeding, egg-laying and waste). Her eggs are fertilized internally, as the male saunters off to his subterranean woodland home.
Each female lays 300-400 eggs in small clusters attached to twigs or leaves in the pond. The eggs develop for two to three weeks before bushy-gilled, long-tailed larvae hatch—complete with well-developed mouths. These quarter-inch eating machines spend about 100 days swimming laps on a carnivorous feeding frenzy, gulping down any moving critter they can fit in their mouths. By June or July they have grown legs and developed lungs during metamorphosis. They climb out of the water and begin the terrestrial part of their life.
Adult salamanders continue the carnivorous lifestyle established as larva, feeding on their roommates in rotting logs, such as worms, slugs, beetles and centipedes. Salamanders even eat their own slimy shed skins! While nutrition is not the primary function of a salamander’s skin, it might be surprising to learn that breathing actually is. In addition to small lungs, salamander skin also acts as a breathing organ, which must stay moist to aid in the exchange of gases. The oozy mucus that keeps their bodies slimy is secreted by skin glands. This slime not only allows the animals to breathe, but it also keeps them safe from predators, such as raccoons and skunks. Special glands in the tail excrete a milky, noxious liquid when the salamander is threatened. When approached by a predator, a blue-spotted salamander holds its body still and wiggles its tail back and forth, luring the predator to strike its tail. Often, the predator ends up with a bit of tail and a mouthful of sticky slime, while the salamander slinks away to safety. Over time, the tail will regenerate as the salamander carries on its life.
This year at the Lake County Forest Preserves we are exploring the unexpected ways in which “Soil Sustains Life.” A variety of programs and events focus on the sustainability of healthy soils from the preserves to your own backyard. We’ll highlight the amazing abundance of life that soil supports and how the unique soil and landscapes of Lake County formed. Certainly, blue-spotted salamanders depend on healthy soils not only for food, but for habitat as well. Come join us to learn more!