Eastern Hellbenders are aquatic amphibians that spend their entire lives in water. They prefer cool, shallow rivers where rocks are not embedded in sediment or silted in. These conditions exist in many parts of the Blue River
Clean water is important for Hellbenders because they obtain most of their oxygen from the water by “breathing” through their skin. When breathing, their fleshy folds expand in surface area, enabling them to absorb more oxygen from the water.
Adults are typically active at night or on overcast days, and otherwise remain hidden under rocks and other cover. When foraging, hellbenders walk along the bottom searching crevices for prey. Their diet consists almost entirely of crayfish, though they will also eat some small fish and aquatic insects. Hellbenders have small eyes and rely primarily on smell to locate prey.
Eastern Hellbenders are one of the few salamander species to externally fertilize eggs. As the female begins to deposit eggs, the male will simultaneously release sperm to fertilize her clutch. Females lay between 100-300 eggs under a male’s nest rock. Individual eggs are attached to each other and have a stringy, beaded appearance resembling a pearl necklace (see the top picture in the diagram below). After egg laying is complete, the male drives off the female and defends the eggs from predators, which include other hellbenders. Eggs hatch into 1-2 inch larvae after 55-75 days. The newly hatched larvae can survive for several months without eating by absorbing nutrients stored in their yolk.
Little is known about the larval life cycle, but they are thought to feed on a variety of aquatic insects and live under gravel and cobble to avoid predators. It is during this larval stage that individuals are the most vulnerable to predation by fish, crayfish, and other aquatic organisms. The larval stage lasts for approximately two years at which point the young undergo a partial transformation. During this life stage, young absorb their gills and begin breathing through their skin. After transformation, juveniles require another three to four years to reach sexual maturity (pictured to the right).