Woodlouse Names: From Slaters and Chucky Pigs to Monkey Peas

Few creatures in the world have accumulated as many nicknames as the humble woodlouse. These small, grey, segmented animals are a familiar sight in gardens across the UK and Ireland, yet what you call them likely depends entirely on where you grew up. Surveys conducted by the University of Edinburgh and other institutions over the past decade have recorded between 250 and 300 traditional names for woodlice across the British Isles alone.

You might know them as woodlice, slaters, chucky pigs, cheese-logs, or monkey peas. Each name carries a story of regional identity, childhood learning, and centuries of folk vocabulary. This article explores the rich tapestry of woodlouse names in English, with particular focus on UK and Irish dialects, touching on how these names cluster into families, why they’re disappearing, and what they tell us about language and nature.

The main name groups we’ll cover include:

• Standard terms (woodlouse, slater)

• Pig-related names (chucky pig, sow bug, penny sow)

• Cheese and food names (cheesy bob, cheese bug)

• Grandparent names (granny grey, granfer grey)

• Borrowed insect names (forky-tailer, monkey-pede)

• Rare regional oddities

What is a woodlouse? (and why the name is confusing)

The term “woodlouse” serves as the standard modern English name for small, grey, segmented terrestrial isopods belonging to the suborder Oniscidea. Despite their bug-like appearance, woodlice are not insects at all—they’re crustaceans, making them more closely related to crabs and shrimps than to beetles or spiders.

Key biological facts about woodlice:

• They possess seven pairs of jointed legs, a defining characteristic of isopods

• They breathe through modified gills or specialised structures called “pleopodal lungs”

• They feed primarily on decaying organic matter, functioning as important garden detritivores

• The “louse” in their name is misleading: unlike true lice (order Phthiraptera), woodlice are not parasitic, and their specialised anatomy reflects their crustacean origins rather than those of insects

The evolutionary history of these creatures stretches back hundreds of millions of years. Marine isopods colonised land during the Carboniferous period, roughly 359 to 299 million years ago. Fossil woodlice clearly identifiable as terrestrial species have been found in mid-Cretaceous amber dating to approximately 100 million years ago. This remarkable evolution from sea to land makes woodlice unusual among crustaceans and helps explain why, as fully terrestrial isopods, they are poorly adapted to activities like swimming in water.

Scientists have validated approximately 3,710 woodlouse species worldwide, with estimates suggesting between 5,000 and 7,000 species exist globally. The most commonly encountered species in the UK, Armadillidium vulgare (the common pill bug), represents just one member of this diverse group, which can be grouped into several major woodlouse types and classifications. However, the majority of folk names do not distinguish between species—to most children and adults alike, a woodlouse is simply a woodlouse, regardless of which species it belongs to.

How many names do woodlice have?

The sheer number of different names for woodlice across the British Isles is extraordinary. Research conducted by Warren Maguire and Tamsin Blaxter at the University of Edinburgh collected traditional names through dialect surveys spanning Scotland, England, Wales, and Ireland. Their work revealed around 250 distinct names in Scottish-focused surveys alone, with broader UK and Irish mapping identifying over 300 separate terms.

A separate popular-science tally cited “176 nicknames” as a memorable figure, though this appears to represent an earlier or more conservative count. More recent, systematic survey work suggests the true number is considerably higher when regional variations and spellings are included.

Many of these “different” names are actually local variants or slight sound changes of the same base word. The family of pig-related names illustrates this perfectly, even though all these terms ultimately refer back to the same common woodlouse:

• Chucky pig

• Chuggy pig

• Chicky pig

• Chiggy pig

• Chiggy wig

These variations often reflect local pronunciation patterns rather than entirely independent inventions. Nevertheless, the diversity is genuine and substantial.

The names cluster into recognisable families based on recurring themes:

• Pigs and sows (chucky pig, sow bug, fat pig, penny sow)

• Cheese and food (cheesy bob, cheese bug, monkey pea)

• Grandparents and family (granny grey, granfer grey, daddy-granfer)

• Borrowed bug names (forky-tailer, bibble bug, coffin cutter)

• Personal names (Billy-baker, Billy-button)

Understanding these categories helps make sense of the bewildering variety of woodlouse words still in use across the UK and Ireland.

Standard and near-standard names

Despite the rich dialectal diversity documented in surveys, a handful of names dominate responses across the UK and Ireland. These standard terms are increasingly the only names younger speakers recognise.

Woodlouse emerges as the most common modern term, appearing in approximately 40-45% of responses in UK and Irish surveys. This name is especially standard in England, Wales, and the Republic of Ireland. The etymology is straightforward: woodlice are frequently discovered in old wood, and their segmented bodies bear a superficial resemblance to lice. The name reflects habitat association and visual comparison rather than biological accuracy—these creatures are neither wood-dwelling exclusively nor related to parasitic lice.

Slater represents the main competitor to woodlouse, accounting for roughly a quarter of all responses. This term dominates in Scotland and Northern Ireland, with related forms like “slatey” or “slate-back” appearing in some areas. The origin likely connects to slate or stone—the rocks and damp surfaces where woodlice congregate. Some researchers suggest it may derive from an older word for grey or slate-coloured.

Key observations about standard names:

• Woodlouse is gaining ground among younger speakers across all regions

• Slater remains robust in Scotland but shows signs of retreating in some Northern Irish areas

• Both terms are replacing older local nicknames in most communities

• Media, education, and national standardisation appear to drive this change

Pig and “chucky pig” names

A very large share of dialect names link woodlice to pigs—pig, sow, hog, and grunt all appear in recorded terms. This association likely reflects the creatures’ rounded bodies and their “foraging” behaviour as they root through leaf litter and decaying wood. The pig connection appears across multiple linguistic traditions, suggesting it represents an intuitive comparison that arose independently in different communities.

The chucky pig family of names represents one of the most distinctive regional clusters in British dialectology. These terms concentrate especially in south-west England: Bath, Bristol, Devon, and North Devon appear as strongholds in both 20th-century dialect surveys and modern mapping projects. The variations include:

Other pig-related forms appear in specific locations across the British Isles:

• Parson’s pig – Isle of Man

• Fat pig – around Cork, Ireland

• Penny sow – Pembrokeshire, Wales

• Sow bug – Cambridgeshire, Essex, Hertfordshire corridor

• Sow pigs – scattered East Anglian examples

• Wood pig – various locations

Statistical analysis of UK and Irish datasets suggests that porcine names collectively represent roughly one fifth (about 19%) of all woodlouse names recorded. This makes the pig family the second-largest category after standard terms, reflecting how deeply embedded these associations are in rural British and Irish culture and how strongly people associate woodlice with the larger, more conspicuous ball-rolling “pill” woodlice found under stones and logs.

Cheese, grandmothers, and other themed nicknames

Beyond pigs, many woodlouse name clusters are based on playful images: food items like cheese and peas, elderly relatives, or personal names like Billy. These themed nicknames reveal how children and communities have creatively named the creatures in their environment.

Cheese names concentrate in southern England, with “cheese-log” and “cheesy bob” among the most commonly recorded. The cheese bug variant appears in overlapping regions. Historical records show related forms like “cheslop” or “chestlokes” attested from the 1500s onward, suggesting these names have considerable antiquity. Dialect maps suggest a spatial progression: older cheese-log forms appear to trend north-west, while newer forms like cheese-bob and cheese-bug spread south-east. The cheese association may reference the creatures’ grey colour or their segmented, log-like appearance.

Grandparent names connect the grey colouration of woodlice to imagery of elderly relatives. Examples include:

• Granny grey – Bridgend, Rhondda, Caerphilly (South Wales valleys)

• Granny grunter – Isle of Man

• Granfer grey – Somerset, Devon

• Daddy-granfer – Bristol area

• Grandfather – scattered usage

The grey/grey-haired connection seems obvious, though some researchers suggest the slow, deliberate movement of woodlice may also contribute to the “old person” association.

Billy and personal names represent a localised but fascinating category. English dialects frequently assign human names to plants and animals, and woodlice are no exception:

• Billy-baker – Yeovil

• Curly-baker – Somerset area

• Billy-button – Weymouth

• Belly button – Bournemouth

The shift from “Billy-button” to “belly button” demonstrates how names can drift through mishearing or playful adaptation over generations.

Monkey and pea names cluster primarily in Kent:

• Monkey pea – east Kent

• Monkey pease – variant spelling

• Pea-bug – north and west Kent

Rare forms like “monkey-pede” may show influence from “millipede” or “centipede,” blurring the lines between different groups of segmented creatures in folk taxonomy.

Borrowed names from other “creepy-crawlies”

Many woodlouse names are recycled from other insects and arthropods, particularly earwigs, centipedes, and millipedes. This borrowing reflects the fluid boundaries between “bug” categories in folk taxonomy—where one small, many-legged creature may receive a name originally applied to another.

Earwig-derived names appear especially in Scotland and northern England. Examples include:

• Eary-wig – borrowed directly from earwig terminology

• Forky-tailer – references the pincers of earwigs, misapplied to woodlice

• Forky-goller – Scottish variant

These matches with local earwig names likely reflect simple confusion, or perhaps playful transfer by children who group all small garden creatures together. The fact that woodlice lack the distinctive pincers of earwigs doesn’t seem to have prevented the name transfer.

Some names reference millipedes:

• Monkey-pede – possible millipede influence

• Generic terms like “millipede-bug” appear in anecdotal reports

The distribution of these borrowed names suggests multiple independent inventions rather than a single word spreading nationwide. Different communities apparently reached similar naming solutions when faced with the challenge of categorising small, segmented creatures found under rocks and in damp wood.

This naming pattern shows that folk taxonomy operates on different principles than scientific classification. Where biologists carefully distinguish between isopods, insects, and myriapods (the group containing centipedes and millipedes), traditional naming groups animals by appearance, behaviour, or habitat association.

Oddities and rare one-off names

Beyond the major clusters, surveys have uncovered many rare, sometimes unique local words for woodlice. These oddities fascinate researchers precisely because they’re so difficult to explain.

The “leather-jacket” family of names appears scattered across eastern England. Variants include joking forms like “bomber-jacket” and “grandfather’s jacket,” possibly inspired by the tough exoskeleton or clothing metaphors. Whether these represent genuine traditional dialect words or modern inventions remains unclear.

Miscellaneous “-back” names appear mainly in north-west England:

• Stone-back – referencing habitat

• Slate-back – connected to slater terminology

The coffin cutter name appears in isolated records, though its origin remains mysterious. Some researchers speculate it may relate to the creatures’ presence in damp, underground spaces, though this explanation seems speculative.

For many of these one-off forms, researchers cannot determine whether they are:

• Genuine dialect words passed down through generations

• Family in-jokes or household terms

• Transcription errors or misheard responses in surveys

• Recent inventions by playful respondents

These oddities illustrate how inventive and localised children’s naming practices can be. A single family might develop its own term for woodlice, used nowhere else in the world, and that term might persist for generations within that household before finally being documented by a passing researcher.

The big picture: change, loss, and standardisation

Dialect surveys comparing older records from the late 19th and 20th centuries with 21st-century data reveal rapid loss of local woodlouse names. The trajectory is clear: regional diversity is collapsing toward standardisation.

Woodlouse now dominates across most of the UK and Ireland, especially among younger speakers. Slater remains strong in Scotland but shows signs of retreating in some Northern Irish areas where it once held unchallenged dominance. The patterns visible in survey maps suggest this isn’t gradual drift but relatively rapid change occurring within a few generations.

Many pig-related, cheese-related, and grandparent names survive only in pockets:

• Billy-baker persists around Yeovil

• Cheese-log holds on near Reading

• Chucky pig variants remain in parts of Devon and Bristol

• Granny grey appears in South Wales valleys

These names increasingly belong to older speakers and are not being transmitted to children. When researchers ask where respondents learned their term for woodlice, younger people typically cite school, television, or books—media that favour standard terminology.

This trend connects to wider linguistic patterns affecting all regional vocabulary:

• Dialect levelling – regional differences smoothing out under pressure from standard English

• Media influence – television, internet, and national publishing promoting standard terms

• Education standardisation – nature study in schools using scientific or national terminology

• Reduced rural vocabulary transmission – fewer children learning words from agricultural contexts

Similar pressures likely affect woodlouse names in other English-speaking regions. In the United States, “pill bug” and “roly poly” dominate, with the potato bug variant appearing regionally. However, systematic data comparable to UK surveys remains patchy for North America, Australia, and other Anglophone areas.

Beyond English: woodlouse names in other languages

The “pig” and “rolling” themes in woodlouse names are not limited to English dialects. Cross-linguistic comparison reveals that multiple language communities have independently reached similar naming solutions.

Welsh provides a clear example with mochyn coed, literally meaning “wood pig.” This parallel to English pig names suggests the rounded body and foraging behaviour of woodlice invite porcine comparison across linguistic boundaries. Similar pig-related terms appear in other European languages, though comprehensive surveys comparable to UK dialectology projects remain rare.

Many languages reference the ability of some woodlouse species to roll into a ball:

Not all woodlouse species can roll into tight balls—some flatten rather than curl—but the dramatic defensive display of conglobating species has clearly captured human attention across cultures. Children worldwide seem particularly drawn to this behaviour, which may explain why rolling-related names appear so frequently in languages that have been surveyed and why this behaviour features prominently in descriptions of the woodlouse life cycle and habits.

Systematic, up-to-date global surveys like the UK woodlouse name projects remain rare. Outside north-western Europe, we mostly have scattered lexicographical notes and anecdotal collections. The British Myriapod and Isopod Group maintains records for the UK, but equivalent organisations don’t exist everywhere.

Why woodlouse names matter to linguists and naturalists

Woodlouse names serve as valuable data points in dialectology, sociolinguistics, and language change research. These humble creatures offer a perfect test case for studying how vocabulary varies across geography and changes over time.

Mapping terms like slater, chucky pig, cheese-log, and granny grey allows researchers to trace historical settlement patterns and cultural contact zones within the UK and Ireland. The distribution of chucky pig variants, for instance, closely matches known dialect boundaries in south-west England. Where pig names give way to cheese names tells us something about historical community connections that might otherwise be invisible.

Folk names preserve information about:

• Behaviour – rolling into balls, foraging in wood

• Habitats – association with wood, stone, cellars, gardens

• Perceived resemblance – pigs, peas, buttons, grey-haired relatives

This information complements biological descriptions by showing how non-specialists perceive and categorise the creatures sharing their environment. The bibble bug might not appear in any biology textbook, but it tells us something about how a particular community understood their local nature and the detritivorous feeding habits of woodlice.

Modern surveys typically run as online questionnaires asking where respondents grew up, what term they use for woodlice, and where they learned it (family, school, friends, pets, etc.). These simple questions generate rich datasets that can be mapped and analysed statistically and have even inspired hobbyist interest in keeping isopod species whose care often depends on understanding their natural habitats and behaviours.

Documenting these names now preserves a slice of cultural heritage that may otherwise vanish within a few generations. When the last speaker who calls woodlice “granfer greys” passes away without transmitting that term to children or grandchildren, that word is lost forever. The survey work happening at places like the University of Edinburgh ensures these words survive at least in archives, even if they fade from living speech, while guides to controlling woodlice in homes and gardens show how these same animals are also framed as everyday household pests.

Whether you call them woodlice, slaters, chucky pigs, or cheesy bobs, these creatures carry centuries of linguistic history in their many names. The next time you turn over a rock or log in your garden and watch these ancient isopods scatter, consider what name rises to your lips—and where that word might have come from.