Large males can exceed 70 mm including the mandibles.
Fine-art photographic collection
Lucanus tsukamotoi
A giant-jawed stag beetle restricted to the forests of Laos and neighbouring Indochina.
About this species
Lucanus tsukamotoiNagai, 2002
Information reviewed15 July 2026
Lucanus tsukamotoi is a large Southeast Asian stag beetle. Males carry elongated antler-like mandibles, while females have shorter, stronger jaws suited to cutting into decaying wood for egg laying.
Taxonomy
Animalia · Arthropoda · Insecta · Coleoptera · Lucanidae · Lucanus
Accepted taxon. · checked 2026-07-15
Laos and neighbouring parts of IndochinaBroad range and selected reference localities — not a complete occurrence map.
Laos and neighbouring parts of Indochina
Mature broadleaf forest with large dead roots, stumps and sap-producing trees.
Adults are mainly active in warm, humid months and visit sap flows, often after dark.
Larvae consume fungus-decayed wood; adults take tree sap and fermenting fruit.
Solitary; males fight at feeding and mating sites.
What makes this species remarkable?
The male’s enormous mandibles are a sexual weapon, not feeding equipment: he uses them to grip, lift and throw rival males from tree trunks.
Females reverse the design priorities — compact bodies and strong cutting jaws allow them to enter rotten wood and place eggs where the larvae’s food already exists.
The spectacular adult is only the final, brief phase of a life spent mostly as a hidden wood-grub, making old decaying timber essential to the species long before any beetle is seen.