The eastern hercules beetle is the largest beetle in the United States. They grow to more than two inches long. Males, slightly larger than females, are olive green in color with patterns of brown spots. Males also have a pair of "horns" extending from the front of their heads. Females are greenish brown and have no horns.
Hercules beetles live in shady areas with lots of plants. After mating, the female beetles pack bits of decaying wood into a pile. She then sticks her ovipositor into the pile and lays an egg. Usually this is in a stump, log, or dead tree. The egg hatches in three to four months, and a larva immediately starts to feed on the dead wood where it is born. It eats and grows for about eight months. When it is ready, the larva changes into the pupa stage by making a hollow shell out of bits of wood and debris, sticking them together with saliva. It rests in this stage until it is ready to emerge as an adult beetle in the spring.
Adult beetles leave their wooden coccoons and fly off in search of food and a mate. Beetles eat sap from young tree saplings that comes out when they rub against the bark. Eastern hercules beetles release a foul-smelling odor to try to discourage predators. They can be eaten by large animals that prey on insects, especially large birds, such as owls and crows. Larvae can be dug out of their wooden shelter by woodpeckers and other animals.