Stag Beetle
The stag beetle is one of the biggest and most impressive beetles in Europe. Males have huge jaws that look like the antlers of a stag (a male deer), which is how the beetle got its name. Its scientific name is Lucanus cervus, and it belongs to a family of about 1,200 stag beetle species found around the world.
European stag beetle Quick Facts
| Common name | European stag beetle |
| Scientific name | Lucanus cervus |
| Kingdom | Animalia |
| Phylum | Arthropoda |
| Class | Insecta |
| Order | Coleoptera |
| Family | Lucanidae |
| Genus | Lucanus |
| Type | Insect (stag beetle) |
| Diet | Larvae eat rotting wood; adults may sip sap or fruit juice |
| Habitat | Woodland edges, parks, gardens and hedgerows with dead wood |
| Native range | Europe, including southern Britain |
| Size | Males about 3.5-7.5 cm; females about 3-5 cm |
| Lifespan | Up to about 7 years, mostly as a larva; adults live a few weeks |
| Special feature | Males have huge antler-like jaws |
Despite their fierce look, stag beetles are harmless to people and are a welcome sight in gardens and woodlands.
What Stag Beetles Look Like
Male European stag beetles are usually about 3.5 to 7.5 cm long, including their giant jaws, which are called mandibles. Females are smaller, around 3 to 5 cm, with short but strong jaws. The head and body are shiny black, and the wing covers (elytra) are a rich chestnut or reddish brown.
Stag beetles have bent, elbowed antennae with a little comb of flat plates at the tip. These plates help them pick up smells, including the scent of a possible mate.
The name Lucanus is very old. The Roman writer Pliny the Elder said stag beetles were worn as charms in Lucania, a region of Italy. Cervus is Latin for deer.
Life Cycle
Stag beetles spend almost all of their lives hidden underground as larvae. In summer, the female digs into the soil next to an old rotting stump or buried log and lays her eggs there.
Each egg hatches into a soft, creamy white, C-shaped grub with an orange-brown head. The larva spends the next few years chewing through damp, decaying wood. It grows slowly, molting its skin as it gets bigger, and can reach about 10 cm long. This underground stage usually lasts 3 to 7 years, and longer when the weather is cold.
When it is fully grown, the larva builds a large chamber of soil, about the size of an orange, where it turns into a pupa. The adult beetle forms in the autumn but stays underground through the winter, then digs its way out in late spring or early summer.
Life above ground is short. Adults live only a few weeks, mostly from May to August. They hardly eat at all, living mainly on fat stored as larvae, though they may sip tree sap or juice from rotting fruit.
Fighting and Finding a Mate
On warm summer evenings, male stag beetles fly around slowly in search of females. They make a loud buzzing sound and fly in a nearly upright position.
When two males meet, they may wrestle with their jaws, much like deer clash their antlers. Each one tries to grab the other and lift him, flip him over or push him off a log or branch. The winner gets the chance to mate. Most fights end without serious injury, though males are sometimes hurt.
Females can fly but usually do not travel far. They tend to stay close to the area where they grew up, which is one reason stag beetles have a hard time spreading to new places.
Are Stag Beetles Pests?
No. Stag beetle larvae eat only dead wood that is already rotting. They do not harm living trees, garden plants, crops or houses. In fact, they are helpful, because they break down dead wood and return nutrients to the soil.
If you pick up a male, his big jaws can give a pinch, but they are not very strong. The female’s smaller jaws can give a sharper nip, so it is best to watch stag beetles rather than handle them. If one is in danger on a path or road, you can gently move it onto a piece of wood or leaves.
Other stag beetle species live in North America, including the large giant stag beetle of the eastern United States. They are also harmless and live in rotting wood.
Amazing Stag Beetle Facts
Stag Beetle – Photo by: Eddy Van 3000
- The stag beetle is one of Britain’s largest native land beetles.
- Old country names for stag beetles include billywitch, oak-ox, thunder beetle and horse pincher.
- People in Britain, Germany and ancient Greece told many stories and superstitions about them.
- From egg to adult, a stag beetle’s life can take up to about seven years, yet the adult may live only a few weeks.
- Males fly mostly at dusk, when the air is warm.
Why Are Stag Beetles in Trouble?
Stag beetles have disappeared from many parts of Europe, and they are protected by law in the UK and several other countries. Parts of southern England, including London, are among their last strongholds in Britain.
The biggest problem is the loss of dead wood. When old trees, stumps and fallen logs are cleared away from woods, parks and gardens, the larvae lose their food and home. Adults also face dangers above ground from cars, cats, foxes, magpies and crows.
You can help stag beetles by:
- Leaving old stumps and dead wood in place instead of removing them.
- Building a log pile in a shady spot, with some logs partly buried in the soil.
- Avoiding garden chemicals near log piles and leaf litter.
- Reporting any stag beetles you see to a local wildlife survey.
European stag beetle FAQs
Do stag beetles bite?
They can pinch if handled, but they are not aggressive. A male’s large jaws are not very strong, while a female’s smaller jaws can give a sharper nip. It is best to watch them and leave them alone.
How long do stag beetles live?
Stag beetles can live up to about seven years, but nearly all of that time is spent underground as a larva eating rotting wood. Adults live only a few weeks in summer.
Are stag beetles endangered?
They have declined in many parts of Europe and are protected in the UK and several other countries. They are not listed as endangered worldwide, but losing dead wood is a serious threat to them.
What do stag beetles eat?
The larvae eat damp, rotting wood such as old stumps and buried logs. Adults eat very little and live mostly on fat stored as larvae, though they may sip sap or fruit juice.
Are stag beetles harmful to trees or gardens?
No. Stag beetle larvae only eat dead wood that is already decaying, so they do not hurt living trees, plants or houses. They actually help recycle dead wood into soil.
Randi Jones is the owner and founder of the Nature Gift Store, an online retailer specializing in nature-themed gifts, educational science projects, live animal nature kits and real butterfly artwork. A biology graduate who fell in love with insects, she founded the company in 2001 to make active learning about nature fun, accessible and engaging for children and adults. Her store offers real butterfly frames, home and garden decor and educational live animal kits, including ant farms, worm farms, tadpoles, ladybugs and hermit crabs, and she runs a bug museum in Washington featuring live animals like Eddie the Iguana alongside other reptiles and insects.
