What the sources say
Stag BeetleLucanus cervus
Every figure, record and mechanism on the Stag Beetle profile was written from a source, and this is the working table behind it: 44 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.
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Source
01
Natural History Museum, London
Stag beetles: Facts about the UK's largest beetle and where to see it. Natural History Museum, London.
- The page saysA male stag beetle can measure up to 7.5 centimeters long, jaws included, making it the largest beetle in the UK and in Europe
- The source says
Male stag beetles measure up to 7.5 centimetres long when their impressive jaws are taken into account, making this species the largest beetle in the UK and in fact the whole of Europe.
- The page saysMales run 35 to 75 millimeters and females 30 to 50 millimeters
- The source says
Length, including mandibles/jaws: males 35-75mm long, females 30-50mm long
Note: the facts box gives these lengths with no UK scope, so the page no longer calls them British - The page saysadults weigh 2 to 6 grams
- The source says
Weight: 2-6 grams
- The page saysMales use those oversized jaws to battle each other for access to females
- The source says
Male stag beetles use their large, antler-like jaws to battle each other for access to females during breeding season
- The page saysraises them as a warning to rivals
- The source says
Male stag beetles use their magnificent mandibles as a warning signal to other males, raising them in a defensive or aggressive posture to fight off a contender.
Note: body and faq 1 - The page sayseach beetle tries to pry the other loose from where it clings, and the more similar their jaw size, the longer the battle lasts
- The source says
The male beetles spend a lot of time and effort dislodging their opponent from where it clings. The more similar the jaw size of the rivals, the longer the battles last.
Note: body and faq 1 - The page saysSkilled wrestlers
- The source says
These beetles are skilful wrestlers
Note: blockquote lead - The page sayscan even stand up on his hind legs to throw an opponent, and the largest beetle almost always wins
- The source says
These beetles are skilful wrestlers and can even stand up on their hind legs to throw an opponent. ... The largest individual almost always wins.
Note: body and faq 1 - The page saysA stag beetle typically lives three to seven years, and spends most of that time as a larva underground
- The source says
Stag beetles live between three and seven years, on average. The vast majority of this time is spent as a larva underground
Note: body and faq 3; 'most' says less than 'the vast majority' - The page saysan egg hatches after about three weeks
- The source says
The eggs hatch after about three weeks
- The page saysA larva can grow to around 11 centimeters, longer than the adults
- The source says
Male stag beetles measure up to 7.5 centimetres long ... The size of stag beetle larvae is even more impressive than the adult beetles. They can grow to around 11 centimetres long.
Note: 'longer than the adults' compares the page's own two figures: larvae around 11 cm, adults up to 7.5 cm - The page saysAfter about six weeks as a pupa, the adult stays underground until the following May or June, usually digging its way out after warm summer rains, when the ground is softer
- The source says
Pupation takes about six weeks ... The transformed adult leaves the pupa but remains underground until the following May or June when they emerge ... They usually burrow their way to the surface after warm summer rains when the ground is softer.
- The page saysdoesn't eat solid food: it drinks sweet fluids such as tree sap and the juice of rotting fruit, and mostly relies on energy stored as a larva
- The source says
Adult stag beetles don't eat, but they do drink sweet fluids such as tree sap and the liquid from decomposing fruit. They mostly rely on the energy stores they built up as a larva.
Note: body and faq 3; 'solid food' because the same sentence says they drink - The page saysonly a few weeks left to find a mate before it dies, usually by August
- The source says
Once above ground, adults only survive for a few weeks and their sole purpose is to mate. ... Adult stag beetles generally die soon after mating and egg laying, usually by August.
Note: body and faq 3; 'before it dies' is the page's 'die soon after mating' - The page saysStag beetles rely on dead wood, and losing it is the main reason the species is struggling, as woodland, parks and gardens are tidied up and broadleaf woodland becomes farmland, plantations and towns
- The source says
The main reason the species is struggling is the loss of its key habitat - dead wood - due to the tidying up of woodland, parks and gardens, and as broad-leaved woodland has been turned into farmland, forestry plantations and urban developments. Stag beetles rely on rotting tree stumps and other dead wood.
- The page saysDespite their intimidating appearance, stag beetles are harmless to people
- The source says
despite their intimidating appearance, stag beetles are harmless
- The page saysA male can give a bit of a pinch, but only if you encourage him; a female's jaws are a bit stronger and can bite, but females aren't aggressive
- The source says
The males can move their jaws just enough to give you a bit of a pinch, but they will only do so if you encourage them. The females' jaws are a bit stronger and capable of biting, but they aren't aggressive.
Note: body and faq 2 - The page saysStag beetles break down dead wood and return its nutrients to the soil
- The source says
Stag beetles are important for recycling and breaking down dead wood and returning the nutrients to the soil.
- The page saysThey also provide food for birds, and in towns they face a lot of predation from cats, foxes, crows and magpies
- The source says
They also provide food for birds. ... In urban areas, stag beetles are prone to being run over by cars. They also face a lot of predation from cats, foxes, crows and magpies.
Note: the predator list follows the page's sentence on urban areas, so it is scoped to towns - The page saysAntler-like jaws for wrestling rivals
- The source says
Male stag beetles use their large, antler-like jaws to battle each other for access to females ... These beetles are skilful wrestlers
Note: tagline - The page saysyears spent as a larva tunnelling through rotting wood, and just a few weeks as an adult to find a mate
- The source says
Stag beetles live between three and seven years, on average. The vast majority of this time is spent as a larva underground, creating tunnels through the rotting wood they feed on. ... Once above ground, adults only survive for a few weeks and their sole purpose is to mate.
Note: tagline - The page saysWoodland, hedgerows, traditional orchards, and parks and gardens with a lot of dead wood; in the UK mainly southeast England
- The source says
In the UK, stag beetles mainly live in southeast England ... Stag beetles' natural habitat is woodland, but they can also be found in hedgerows, traditional orchards and urban areas, particularly in parks and gardens with a lot of dead wood.
Note: stats.habitat - The page saysAdults drink sweet fluids such as tree sap and the juice of rotting fruit; larvae spend several years feeding on decaying wood, and seem to prefer oak
- The source says
they do drink sweet fluids such as tree sap and the liquid from decomposing fruit. ... The larvae seem to prefer the wood of oak trees ... the larvae then spend several years feeding on decaying wood
Note: stats.diet - The page saysAntler-like mandibles used to pry rival males loose and even throw them.
- The source says
antler-like jaws to battle each other ... can even stand up on their hind legs to throw an opponent. The male beetles spend a lot of time and effort dislodging their opponent from where it clings
Note: stats.superpower - The page saysA male stag beetle's "antlers" are its mandibles, hugely enlarged and used to battle rival males for access to females
- The source says
Male stag beetles use their large, antler-like jaws to battle each other for access to females during breeding season, much like a male deer uses its antlers.
Note: faq 1 - The page saysStag beetles look fierce but are harmless.
- The source says
despite their intimidating appearance, stag beetles are harmless and you can safely pick them up to move them out of harm's way.
Note: faq 2; the quote's 'up to' belongs to 'pick them up to move them', not a hedge on 'harmless' - The page saysThere really is no need to fear these beetles: they are not dangerous.
- The source says
There really is no need to fear these beetles. They are not dangerous. I've never been bitten by one.
Note: faq 2, Max Barclay quote - The page saysfeeding on decaying wood for several years before it pupates
- The source says
the larvae then spend several years feeding on decaying wood. ... Pupation takes about six weeks and begins in the final autumn of the beetle's life cycle.
Note: faq 3; 'several years' is the NHM figure, because the faq cites NHM and not detection-2017's three to five - The page saysa beetle that wrestles: rival males try to pry each other loose from where they cling
- The source says
These beetles are skilful wrestlers ... The male beetles spend a lot of time and effort dislodging their opponent from where it clings.
Note: vibe.reason (task #211); replaces "titanic armored aggression", which no source supports - The page saysa male can stand up on his hind legs to throw an opponent
- The source says
These beetles are skilful wrestlers and can even stand up on their hind legs to throw an opponent.
Note: vibe.reason (task #211)
Source
02
Telnov 2025
Telnov (2025). Lucanus cervus. The IUCN Red List of Threatened Species 2025: e.T239951016A213072777.
- The page saysThe IUCN Red List records it as extinct in Estonia and Lithuania and reintroduced to Denmark
- The source says
Extinct ... Estonia; Lithuania ... Extant & Reintroduced (resident) ... Denmark
Note: hand check: the assessment's range list (assessed 05 July 2023) was read on iucnredlist.org in Chrome on 2026-09-13; it lists Latvia as native and extant, so NHM's 'disappeared entirely from Latvia' is out of date and was cut - The page saysthe Red List currently classifies it as Near Threatened
- The source says
Near Threatened; Date assessed: 05 July 2023
Note: hand check: GBIF has no Red List category on file for IUCN taxon 239951016, and iucnredlist.org refuses scripts, so this was read directly on iucnredlist.org in Chrome on 2026-09-13 (category 'Near Threatened', assessed 05 July 2023). Also used for stats.conservationStatus.
Source
03
Harvey et al. 2011
Harvey et al. (2011). Bionomics and distribution of the stag beetle, Lucanus cervus (L.) across Europe*. Insect Conservation and Diversity.
- The page saysSize varies across Europe: beetles from Spain, Germany and the Netherlands are larger than those from Belgium or the UK
- The source says
Adult size also varies; beetles from Spain, Germany, and the Netherlands are larger than those from Belgium or the UK. In the former countries, populations are composed mainly of large individuals, while in the UK, the majority of individuals are relatively small.
- The page saysIn the UK, most individuals are relatively small
- The source says
in the UK, the majority of individuals are relatively small
Note: "most" for "the majority" - The page saysmost often oak
- The source says
Larvae are most commonly associated with oak
Source
04
Tini et al. 2017
Tini et al. (2017). Detection of stag beetle oviposition sites by combining telemetry and emergence traps. Nature Conservation.
- The page saysFemales lay 15 to 36 eggs in a single clutch, 24 on average
- The source says
its modest reproduction rate (for an insect) that ranges from 15 to 36 eggs (24 on average) for a single clutch
- The page saysThe larva then spends three to five years underground, often up to a meter deep, feeding on decaying wood
- The source says
Its larvae develop underground for three to five years, often up to 1m deep, feeding on decaying wood of stumps, logs or roots of a wide range of broadleaf trees and shrubs
Source
05
Harvey & Gange 2006
Harvey & Gange (2006). Size variation and mating success in the stag beetle, Lucanus cervus. Physiological Entomology.
- The page saysMating success depends on a male's size relative to the female's, and very large males are less successful at it
- The source says
it is the ratio of male : female size that determines mating success. Very large males are less successful in mating
Source
06
Romiti et al. 2015
Romiti et al. (2015). Exaggerated allometric structures in relation to demographic and ecological parameters in Lucanus cervus (Coleoptera: Lucanidae). Journal of Morphology.
- The page saysIn one study, the bigger-jawed "major" males survived at a lower rate than "minor" males
- The source says
This species shows a remarkable dimorphism in mandible shape and size that are used by males in intraspecific combats. Stag beetles were captured, measured, weighed, and released in the framework of a capture-mark-recapture study. ... These results led to a more consistent distinction of males in two morphologies: minor and major. The survival probability of individuals was dependent on the morphological class and was higher for minor males than for major.
Note: 'bigger-jawed': the morphs are split at a switchpoint in mandible length against body size, so major males carry the longer mandibles; 'one study' because it is a single capture-mark-recapture population - The page saysbody fragments left by corvids showed the two forms faced different predation pressure
- The source says
Differences in predatory pressure were detected between morphs by the collection and analysis of body fragments due to the predatory activity of corvids.
Note: the abstract does not say which morph is preyed on more, and the page claims no direction
Source
07
Cox et al. 2019
Cox et al. (2019). Phylogeographic structure and ecological niche modelling reveal signals of isolation and postglacial colonisation in the European stag beetle. PLOS ONE.
- The page saysStag beetles are sedentary: dispersal distances seem to range from a few hundred meters up to a maximum of five kilometers
- The source says
dispersal distances in the species seem to range from a few hundred meters up to a maximum of five kilometres ... The sedentary nature of stag beetles
- The page saysfound widely across Europe
- The source says
is a saproxylic beetle species distributed widely across Europe
Note: body and stats.habitat - The page saysthroughout its range it has shown pronounced declines
- The source says
Throughout its distribution the species has exhibited pronounced declines
- The page saysIt's been protected under the European Union's Habitats Directive since 1992
- The source says
has been protected by the Habitats Directive of the European Union since 1992
How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.