Andy Sands / Stag Beetle (Lucanus cervus) male on Oak branch with woodland ride, West Sussex, England. UK

Andy Sands / Stag Beetle (Lucanus cervus) two males fighting, West Sussex, England. UK

Nick Garbutt / Giant Stag Beetle {Lucanidae} (unknown species) Montane rainforest, Mt Kinabalu, Sabah, Borneo.

Kim Taylor / Stag Beetle (Lucanus cervus) male, UK. Captive.

Hans Christoph Kappel / Stag Beetle on tree trunk (Lucanus cervus) Germany

Hans Christoph Kappel / Stag beetles fighting, Germany

Ingo Arndt / Close-up of mouthparts of Stag beetle (Lucanus cervus)

Chien Lee / Stag Beetle (Odontolabis dalmani) male, Gunung Penrissen, Sarawak, Borneo, Malaysia

Thomas Hinsche/ BIA / Stag Beetle (Lucanus cervus), Saxony-Anhalt, Germany

Chien Lee / Stag Beetle (Lamprima adolphinae) male, Arfak Mountains, West Papua, Indonesia

Solvin Zankl / Stag beetles (Lucanus cervus) fighting on oak tree branch, , Elbe, Germany, June.

Solvin Zankl / Stag beetles (Lucanus cervus) pair mating on oak tree tree, Elbe, Germany, June.