These large herbivores are normally found in or near tree stumps and fallen logs, where they lay eggs; the larvae feed on the decaying wood. Depending on the species, the beetles may be green, tan, gray, reddish brown, dark brown or black.
Despite their ferocious appearance, stag beetles aren't a threat to people or pets. The elongated mandibles on male stag beetles can't be used for biting but instead serve as jousting weapons during mating season; the male uses them to fight with competing males. The size of the mandibles varies with species; those of the giant stag beetle are especially long. The mandible also indicates how much food the male has consumed: The better the diet, the larger the jaw. Females have normal mandibles.
Stag beetles aren't considered pests.