Stag beetles are a family of about 1,200 species of beetles in the family Lucanidae, currently classified in four subfamilies. Some species grow to over 12 centimetres (4+1⁄2 inches), but most to about 5 cm (2 in). Male stag beetles are known for their oversize mandibles used to wrestle each other for favoured mating sites in a way that parallels the way stags fight over females. Fights may also be over food, such as tree sap and decaying fruits. Despite their often fearsome 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, thus disrupting their balance. Because its mandibles are capable of exceeding its own body size, stag beetles are generally inefficient runners, and typically fly from one location to another. 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. (Source: Wikipedia.org, CC BY-SA)