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Stag Beetle (Lucanus cervus) wildlife photograph

Field guide · rare

Stag Beetle

Britain’s largest beetle — antler jaws, dusk flights, and rotting-wood larvae.

Near Threatened

Lucanus cervus

Overview

Stag beetles are Britain’s largest terrestrial beetles, named for the antler-like jaws of adult males. Larvae spend years developing in rotting wood, and adults take clumsy dusk flights on warm summer evenings in southern England.

For UK collectors, the stag beetle is a rare summer icon — massive jaws, southern strongholds, and a flagship of deadwood garden conservation.

Habitat

  • Rotting stump
  • Woodland edge
  • Orchard
  • Garden deadwood

Woodland edges, parks, orchards, and gardens in southern Britain with underground rotting timber — roots, stumps, and buried deadwood for larvae.

Countries found

Field notes

Field scale for the Stag Beetle: length around Males 5-8 cm; females 3-5 cm. Typical lifespan: Adults live weeks to a few months; larvae 3-7 years.

When you are scanning habitat, prioritise rotting stump, woodland edge, orchard, and garden deadwood. Those settings are where a clean look and a usable photo are most likely.

Quick ID anchor: Huge chestnut-black beetle; males have oversized branched mandibles. Confirm with behaviour and habitat before you log the discovery.

Diet

Adults take tree sap and juices from damaged fruit; larvae feed on decaying wood.

Males rarely feed heavily; energy stores from the larval stage fuel adult life.

Behaviour

Males wrestle with mandibles over mating sites near breeding timber.

Adults are most active at dusk; clumsy fliers attracted to warm evenings.

How to identify

Huge chestnut-black beetle; males have oversized branched mandibles.

Females have smaller heads and shorter jaws but a powerful bite.

Interesting facts

  1. 01

    Britain’s largest beetle; males can exceed 7 cm including jaws.

  2. 02

    Male ‘antlers’ are oversized mandibles used in rival sparring.

  3. 03

    Larvae develop for several years in decaying wood.

  4. 04

    Adults fly at dusk on warm summer evenings.

  5. 05

    Strongholds centre on southern England, especially London’s fringes.

  6. 06

    UK Biodiversity Action Plan priority species.

Conservation status

NT: Near Threatened

Stag beetles are Near Threatened across their European range. Loss of deadwood habitat is the main pressure; UK garden log piles and stump retention help local populations.

Sources: IUCN Red List

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