Stag Beetle
Lucanus cervus
Quick answer
The stag beetle is one of Europe's largest beetles, named for the enormous antler-like jaws of the males, which they use to wrestle rivals rather than to bite. Adults are short-lived and feed little, but the larvae spend several years underground developing inside rotting wood. Males can reach 7.5 cm (3 in) long, and the species depends on dead wood, making it vulnerable to tidy land management.
Stag Beetle facts at a glance
| 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) |
| Kingdom | Animalia |
|---|---|
| Phylum | Arthropoda |
| Class | Insecta |
| Order | Coleoptera |
| Family | Lucanidae |
| Genus | Lucanus |
The antler-like jaws
Male stag beetles are famous for their huge, branching mandibles, which resemble the antlers of a stag and give the insect its name. Despite their fearsome look, these jaws are relatively weak and are used mainly to grapple with rival males over mates and territory. Females have much smaller but stronger jaws.
Life cycle
Most of a stag beetle's life is spent underground as a larva, feeding on decaying wood for several years before pupating. The adults that emerge in early summer live only a few weeks to a few months, focusing on finding a mate. This long larval stage means a healthy supply of dead wood is essential for the species.
Diet and behavior
Stag beetle larvae feed on rotting wood, helping to break it down and recycle nutrients in the soil. Adults eat little, taking some tree sap and the juices of soft fruit for energy. On warm summer evenings, males fly in search of females, their large bodies producing a low, buzzing flight.
Conservation
The stag beetle has declined across much of its European range and is listed as Near Threatened, largely because the removal of dead wood and tidy management of woodlands and gardens deprive larvae of habitat. Leaving log piles and dead stumps in place helps support local populations. The species is legally protected in several countries.
Frequently asked questions about the Stag Beetle
Why do stag beetles have such big jaws?
Only male stag beetles have the large antler-like jaws, which they use to wrestle other males over mates rather than to bite. Despite their size, these jaws are fairly weak.
What do stag beetles eat?
Stag beetle larvae feed on rotting wood underground, while the short-lived adults eat little and take only tree sap and the juices of soft fruit for energy.
How long do stag beetles live?
Stag beetles spend most of their life as larvae, developing for three to six years in dead wood. The adults live only a few weeks to a few months after emerging.
Are stag beetles dangerous?
No. Stag beetles are harmless to people, and even the large male jaws are too weak to cause real injury. They do not sting and pose no threat.
Are stag beetles endangered?
Stag beetles are listed as Near Threatened and have declined across much of Europe, mainly because dead wood that their larvae need is often removed. They are legally protected in several countries.
How can I help stag beetles?
Leaving log piles, dead stumps, and decaying wood in gardens and parks provides habitat for stag beetle larvae. Avoiding excessive tidying of woodland and garden areas supports their long underground life stage.
