Stag beetles are a beetle family with about 1,200 species, most of which are about 50mm, but can reach 120mm in some. The common name is derived from the large and distinctive mandibles found on the males of most species, which resemble the antlers of stags.
Male stag beetles use their oversize mandibles to wrestle each other for favoured mating sites in a way that parallels the way stags fight over females. Fighting may also be over food, such as tree sap and decaying fruits. Despite their appearance, they are not normally aggressive to humans. During a battle the main objective is to dislodge its opponent’s tarsal claws with its mandible to disrupt balance. Because of their mandible size, which are often cumbersome, they then to fly from location to location instead of walking. Female stag beetles are usually smaller than the males, with smaller mandibles that are much more powerful than the males. As larvae, females are distinguished by their cream-coloured, fat ovaries visible through the skin around two-thirds of the way down their back. The larvae feed on rotting wood for several years, growing through three larval stages until eventually pupating inside a pupal cell constructed from surrounding wood pieces and soil particles.