mum thought id do a bit of research into the beetle youve found, here goes; Its a male stage beetle (lucanus cervus), it has large powerful jaws that look like branched antlers. The impressive jaws suggest that these beetles catch large pray, but in fact they feed on honeydew and tree sap. The jaws are often used in fights between males over territory, mates, or food. It can grow up to 7cm (3 in) long. So give jack a word of warning dont try to mate with it.