Insects & Invertebrates comparison

Centipede vs Millipede: Key Differences Explained

The short answer

Count the legs per body segment. Centipedes have one pair per segment, flattened bodies and long legs, and are fast predators that subdue prey with venomous forcipules. Millipedes have two pairs per segment, cylindrical bodies and short legs, and are slow detritivores that eat decaying plant material. When threatened a centipede runs or bites, while a millipede coils and may release a defensive chemical.

The main difference

Centipedes have one pair of legs per segment and are venomous predators; millipedes have two pairs per segment and are harmless decomposers.

Both are many-legged animals found under logs and stones, they are constantly conflated, and they occupy opposite ends of the food web.

At a glance

Comparison of Centipede and Millipede across 6 dimensions, with an interpretation of each difference.
What differs	Centipede	Millipede	What it means
Legs per body segment	One pair	Two pairs	The defining structural difference, and the origin of the two class names.
Body shape	Flattened top to bottom, suited to squeezing through crevices while hunting	Cylindrical and tube-like, suited to pushing through soil and litter	Body cross-section follows lifestyle: hunting in gaps against burrowing through litter.
Leg position and length	Long legs projecting sideways, giving a sprawling fast gait	Short legs beneath the body, producing a slow rippling wave of movement	Leg placement is visible at a glance and separates the two immediately.
Diet	Predatory — insects, spiders, worms and, in large species, small vertebrates	Decaying leaves, wood and other plant material	One is a predator, the other a decomposer; their ecological roles are opposite.
Defence	Runs quickly and bites, injecting venom through modified front limbs	Coils into a spiral and may release irritant chemicals	Coiling rather than fleeing is a reliable behavioural cue.
Speed	Fast and erratic	Slow and deliberate	A many-legged animal that bolts is a centipede; one that curls up is a millipede.

Legs per body segment: CentipedeOne pair
MillipedeTwo pairs
The defining structural difference, and the origin of the two class names.
Body shape: CentipedeFlattened top to bottom, suited to squeezing through crevices while hunting
MillipedeCylindrical and tube-like, suited to pushing through soil and litter
Body cross-section follows lifestyle: hunting in gaps against burrowing through litter.
Leg position and length: CentipedeLong legs projecting sideways, giving a sprawling fast gait
MillipedeShort legs beneath the body, producing a slow rippling wave of movement
Leg placement is visible at a glance and separates the two immediately.
Diet: CentipedePredatory — insects, spiders, worms and, in large species, small vertebrates
MillipedeDecaying leaves, wood and other plant material
One is a predator, the other a decomposer; their ecological roles are opposite.
Defence: CentipedeRuns quickly and bites, injecting venom through modified front limbs
MillipedeCoils into a spiral and may release irritant chemicals
Coiling rather than fleeing is a reliable behavioural cue.
Speed: CentipedeFast and erratic
MillipedeSlow and deliberate
A many-legged animal that bolts is a centipede; one that curls up is a millipede.

How they are related

Both are myriapods, but they belong to separate classes — Chilopoda for centipedes and Diplopoda for millipedes — that diverged very early. The doubled legs of millipedes result from pairs of body segments being fused, which is why each apparent segment carries two pairs. Neither is an insect; myriapods form a distinct arthropod group.

Telling them apart

Legs per segment is definitive but needs a close look. In practice, use body shape and behaviour: a flattened, long-legged animal that runs fast is a centipede, while a cylindrical, short-legged animal that moves slowly and curls into a spiral when disturbed is a millipede. Neither name is literal — no centipede has exactly a hundred legs.

Flattened, long-legged, fast, one pair of legs per segment: centipede — a predator with venom. Cylindrical, short-legged, slow, two pairs per segment, curls into a spiral: millipede — a harmless decomposer. Behaviour alone usually settles it: bolting means centipede, curling means millipede.

Habitat and distribution

Both live in damp, dark places — under logs, stones, bark and leaf litter — because both lose water readily through the cuticle. Millipedes are especially associated with deep leaf litter and rotting wood, which is also their food. Centipedes range more widely in search of prey and are more often found in crevices and soil cavities.

Diet and ecological role

Centipedes are predators, using a pair of modified front limbs called forcipules to inject venom and subdue prey — a structure unique to the class and not found in any other arthropod. Millipedes eat decaying plant matter and are important recyclers, breaking litter into smaller fragments that microbes can process, which speeds nutrient return to the soil.

Behaviour

Centipedes are nocturnal hunters, moving quickly and reacting to disturbance by fleeing or biting. Millipedes move slowly through litter and respond to threats by coiling tightly into a spiral, protecting the softer underside, and many secrete defensive compounds from pores along the body. Some of those secretions are strongly irritant and stain skin.

Senses and adaptations

Centipede forcipules are modified first-pair legs converted into venom-injecting fangs, an arrangement unique among arthropods. Millipede defensive glands produce a range of compounds including, in some tropical species, cyanide precursors, and certain primates have been observed deliberately rubbing millipedes on their fur, apparently as an insect repellent.

More on this topic: Animal senses and adaptations.

People and these animals

Millipedes are harmless to people and are valuable decomposers in gardens, woodland and compost. Centipedes control insect populations and larger tropical species can deliver a painful bite, though most temperate species are too small to break human skin. Both are frequently found indoors in damp conditions and both indicate a moist environment.

What they have in common

Both are myriapod arthropods with long segmented bodies and many legs.
Both require damp habitats because they lose water readily through the cuticle.
Both are found under logs, stones and leaf litter and are mainly active at night.
Both add segments and legs as they grow rather than hatching with the full adult count.

Key differences

Centipedes have one pair of legs per segment; millipedes have two.
Centipede bodies are flattened, while millipede bodies are cylindrical.
Centipedes are predators with venomous forcipules; millipedes eat decaying plant matter.
Centipedes flee quickly when disturbed, whereas millipedes coil into a spiral.
Centipede legs project sideways; millipede legs sit beneath the body.

Where people go wrong

Assuming any many-legged animal under a log is the same kind of creature.
Taking the names literally as leg counts.
Treating millipedes as venomous, when they have no venom at all.

Frequently asked questions

How do I tell a centipede from a millipede quickly?

Watch what it does. A centipede runs fast on long legs that project sideways from a flattened body. A millipede moves slowly on short legs beneath a cylindrical body and curls into a tight spiral when disturbed. If you can look closely, count legs per segment: one pair means centipede, two pairs means millipede, and that is the definitive test.

Do centipedes and millipedes really have a hundred and a thousand legs?

No, in both cases. Centipede leg counts vary widely by species but are always an odd number of leg-bearing segments, so exactly a hundred legs is not possible. Millipede counts also vary enormously, and until recently no known species reached a thousand — one deep-soil Australian species described in 2021 finally exceeded it, which was notable precisely because it was unprecedented.

Are millipedes dangerous?

Not in the way centipedes can be. Millipedes have no venom, no biting mouthparts capable of harming a person, and they eat decaying plant material. Their defence is coiling and releasing irritant secretions, which can stain skin and cause irritation, particularly if transferred to the eyes. They should not be handled casually, but they pose no comparable risk.

Why are both found in damp places?

Both lose water readily through the cuticle, lacking the effective waterproofing that insects and arachnids have, so both must stay in humid microhabitats to avoid drying out. Log piles, leaf litter, stones and soil crevices all provide that. It also explains why they appear indoors during dry spells or heavy rain — they are following moisture rather than seeking the building.

Read the full profiles

Sources and methodology

How this comparison is built: FaunaHub comparisons are assembled from the sourced animal profiles behind them rather than written as standalone claims. Figures such as size, mass, and lifespan are typical ranges that vary by subspecies, population, region, sex, age, and — where relevant — whether an animal lives in the wild or under human care, so they are presented as ranges rather than fixed values. Where a common name covers a group rather than a single species, the page says so instead of implying a species-to-species match. Conservation status changes over time and should be confirmed against the current IUCN Red List. Dimensions that could not be supported from the underlying profiles are omitted rather than filled in.

What this page does not do: it does not rank the two animals, predict the outcome of a confrontation, or present either one as stronger, smarter, or better. It is not veterinary, medical, first-aid, handling, capture, hunting, or pest-control guidance. For an animal in your care, or any situation involving injury, contact a qualified veterinarian, your local wildlife authority, or emergency services.

Sources and further reading

Authoritative references used for general educational context. External links open in a new tab. These sources do not endorse FaunaHub.

UniversityAnimal Diversity Web — University of Michigan Museum of Zoology — Peer-edited reference accounts for animal species
ReferenceBritannica — Centipede — Editor-reviewed encyclopedia entry
Wildlife referenceIUCN Red List of Threatened Species — Authoritative source for current conservation status
ReferenceBritannica — Millipede — Editor-reviewed encyclopedia entry
ReferenceEncyclopaedia Britannica — Animals reference — Editor-reviewed encyclopedia overview entries
Wildlife referenceXerces Society for Invertebrate Conservation — Science-based invertebrate conservation resources

Last updated: 2026-08-04