# Stag Beetle (*Lucanus cervus*)

> The stag beetle (Lucanus cervus) is one of Europe's largest land beetles, named for the antler-like jaws that males wave and wrestle with like tiny deer. Adults reach up to 7.5 cm long and live only a few weeks to months, while the grubs spend three to six years feeding on rotting wood underground. Found in old woodlands, parks, and gardens, the species is listed as Near Threatened by the IUCN, largely because dead wood is being cleared from the landscape.

- **Category:** Insect
- **Conservation status (IUCN):** Near Threatened
- **Range:** Old woodlands and parks across Europe and parts of western Asia.
- **Canonical page:** https://globalanimalguide.org/animals/stag-beetle/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Arthropoda
- **Class:** Insecta
- **Order:** Coleoptera
- **Family:** Lucanidae
- **Genus:** Lucanus

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Lucanus cervus |
| Diet | Larvae eat rotting wood; adults take tree sap and fruit juices |
| Habitat | Old woodlands, parks, and gardens with dead wood |
| Lifespan | Larvae 3–6 years; adults a few weeks to months |
| Length | Up to 7.5 cm (3 in) in large males |
| Jaws | Antler-like mandibles in males |
| Conservation status | Near Threatened (IUCN) |

## The antler-like jaws

Male stag beetles are unmistakable, sporting enormously enlarged mandibles that curve and branch like a stag's antlers. Despite their fearsome look these jaws are surprisingly weak and are used mainly for display and for wrestling rival males, not for feeding. In contests over females or feeding sites, two males lock jaws and try to lift and throw each other off the branch. Females lack the great antlers but have smaller, sharper jaws that can actually deliver a stronger pinch.

## A long life underground

The stag beetle spends the overwhelming majority of its life hidden as a larva, not as the familiar adult. The grubs live for three to six years buried in rotting wood, chewing through decaying stumps and roots and growing to the size of a finger. When fully grown a larva builds a cocoon of soil and wood in which it pupates and transforms. This long development is why a steady supply of dead wood is so essential to the species.

## What stag beetles eat

Diet changes completely between the two life stages. The larvae feed on rotting, fungus-softened wood, doing important work breaking down dead timber and returning its nutrients to the soil. Adults, by contrast, do not eat solid food at all; they survive on their fat reserves and sip only sap oozing from trees and juice from fallen, over-ripe fruit. Because the adults barely feed, their whole above-ground life is devoted to breeding.

## The brief adult summer

After years underground, adult stag beetles emerge in early summer to mate, and their winged life lasts only a few weeks to a couple of months. Males take to the air on warm evenings, flying heavily with their bulky bodies held almost upright as they search for females. This is when people most often spot them, blundering around gardens and woodland edges at dusk. Once they have mated and the females have laid their eggs in dead wood, the adults die.

## Why stag beetles are declining

The stag beetle is listed as Near Threatened by the IUCN and has vanished from parts of its former European range. Its decline is driven chiefly by the loss of the dead and decaying wood its larvae depend on, as woodlands are tidied, stumps removed, and fallen timber cleared away. Roads and predators take a further toll on the slow, low-flying adults. Leaving log piles and dead wood in gardens and parks is one of the most effective ways to help the species recover.

## Frequently asked questions

### Why do stag beetles have such big jaws?

Only the males have the large antler-like jaws, and they use them mainly for display and for wrestling other males over females and feeding sites. The jaws look powerful but are fairly weak; a male tries to grip a rival and flip him off the branch rather than injure him.

### Do stag beetles bite?

They can, but they are not aggressive. A female's smaller jaws are strong enough to give a noticeable nip if she is handled carelessly, while the male's showy antlers are surprisingly weak. Neither is dangerous to people.

### How long do stag beetles live?

Stag beetles spend three to six years as grubs feeding on rotting wood underground. Once they emerge as adults, they live only a few weeks to a couple of months, just long enough to mate and lay eggs.

### What do stag beetles eat?

The larvae feed on decaying, fungus-softened wood over several years. Adults eat no solid food and instead sip tree sap and the juice of fallen ripe fruit, living mostly off fat reserves built up during the larval stage.

### Are stag beetles endangered?

Stag beetles are listed as Near Threatened by the IUCN and have declined across much of Europe. The main cause is the loss of the dead and rotting wood their larvae need, as woodlands and gardens are tidied and fallen timber is cleared away.

### How can I help stag beetles in my garden?

The best thing you can do is leave dead wood in place. A pile of logs, an old tree stump, or partly buried decaying wood gives the larvae the habitat they need for their long development, and avoiding pesticides helps the adults survive.

## Sources

- [IUCN Red List — Lucanus cervus.](https://www.iucnredlist.org/search?query=Lucanus%20cervus&searchType=species)
- [Animal Diversity Web — Lucanus cervus. University of Michigan Museum of Zoology.](https://animaldiversity.org/accounts/Lucanus_cervus/)
- [Wikipedia — Stag Beetle.](https://en.wikipedia.org/wiki/Lucanus_cervus)

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Source: Global Animal Guide (https://globalanimalguide.org/animals/stag-beetle/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.