How Many Legs Does a Centipede Really Have?

Quick answer: an adult centipede has between 15 and 191 pairs of legs, which is 30 to 382 legs, depending on the species. Every species has an odd number of pairs, so none has exactly 100 legs. In Britain the counts run from 15 pairs (30 legs) in the brown stone centipedes found in gardens to as many as 101 pairs (202 legs) in a rare soil centipede from Cornwall.

How Many Legs Does a Centipede Have?

Centipedes make up the class Chilopoda, one of the groups of myriapods, the many-legged invertebrates with long, segmented bodies. Each leg-bearing segment of a centipede's trunk carries one pair of legs, so the number of legs depends on the number of segments. About 3,300 species have been described, in five living orders, and the order largely decides the count:

• House centipedes (Scutigeromorpha): 15 pairs, 30 legs.
• Stone centipedes (Lithobiomorpha), including the brown centipede, Lithobius forficatus, a regular in British gardens: 15 pairs, 30 legs.
• Craterostigmus (Craterostigmomorpha), a small order: 15 pairs, 30 legs.
• Giant centipedes and their relatives (Scolopendromorpha): 21 or 23 pairs, 42 or 46 legs. One Brazilian species, Scolopendropsis duplicata, breaks the pattern with 39 or 43 pairs. In Britain the order is represented by species such as Cryptops hortensis, which has 21 pairs.
• Soil centipedes (Geophilomorpha), slim, thread-like animals: 27 to 191 pairs, 54 to 382 legs, depending on the species. British examples include the common western yellow centipede (Stigmatogaster subterranea, also listed as Haplophilus subterraneus), with 77 to 83 pairs, and the rare Stigmatogaster souletina, known from a handful of sites around Falmouth in Cornwall, with 93 to 101.

The record holder is Gonibregmatus plurimipes, a soil centipede from Fiji with 191 pairs (382 legs), described in 1920 from a single specimen. These totals leave out the venom claws, a modified first pair of legs covered further down.

About 50 species of centipede live wild in Britain and Ireland, with another seven introduced species found only in heated glasshouses. Our guide to British centipedes covers how to tell them apart.

Why Is the Number of Pairs Always Odd?

Every centipede species has an odd number of leg pairs as an adult: 15, 21, 23, 27 and on up to 191. The counts jump from 15 straight to 21, so no centipede species has 17 or 19 pairs. A total of 100 legs would need 50 pairs, an even number, which is why no species has exactly 100 legs. The nearest real totals are 98 and 102 legs, and both turn up in Strigamia maritima, a slim seashore centipede of northern Europe, found on Scottish coasts, which has 45 to 51 pairs.

Why the rule holds is still not fully understood. Researchers at Cambridge and Galway who studied embryos of Strigamia maritima from the coast of north-eastern Scotland found that the embryo first marks out its trunk segments two at a time. Each double unit then splits into two single segments, and each of those grows a pair of legs. If segments are made in pairs, evolution would add or remove them in pairs, which keeps an odd number odd. Counted together with the segment that carries the venom claws, a centipede's trunk has an even number of segments.

The rule describes species, not every single animal. In 2009, researchers who examined 809 western yellow centipedes from an unusual, probably introduced population in Poznań, Poland, found three adult males with 80 pairs. One of them was otherwise perfectly formed, and the team described it as the first record of its kind in adult centipedes. The species is common across much of Britain, where it has 77 to 83 pairs.

Centipede Legs Are More Than Just for Walking

The front pair: venom claws

The first pair of legs on the trunk, just behind the head, does not walk. It is turned into a pair of venom claws called forcipules, which are found in no other animal. Each claw ends in a hooked tip, and its base usually holds a venom gland; a centipede uses them to seize prey and inject venom. They are modified legs, not mouthparts. Centipedes split from the other myriapods at least 460 million years ago, and their venom claws are among the oldest venom systems known in land animals. Large tropical centipedes can give a painful bite, while the species found in the British Isles are harmless to people.

The back pair: the ultimate legs

The last pair, the ultimate legs, is usually not used for walking. A 2019 study of the brown centipede's ultimate legs concluded that they serve mainly in defence but also as sense organs, and the animal uses its antennae and long back legs to feel its way around. Tropical giant centipedes raise theirs in a warning display when touched from behind, sometimes strike with them, and interlock them with a partner before mating. Alipes centipedes have broad, leaf-like ultimate legs that make a hissing sound, possibly to warn off predators, and a leg that has been shed keeps hissing after it comes off.

How Centipedes Grow Their Legs

How a centipede reaches its adult count depends on its order.

• Adding legs as they grow (anamorphic development). House centipedes, stone centipedes and Craterostigmus hatch with fewer legs and add more at their early moults. A house centipede hatches with 4 pairs, then has 5, 7, 9, 11 and 13 before reaching 15, so its very first stage has an even number. Young stone centipedes start with 7 pairs. Growing up can take two or three years.
• Hatching with them all (epimorphic development). Soil centipedes and the giant centipedes and their relatives grow every pair inside the egg, so the young hatch with the adult number and never add segments.

Centipede vs Millipede: Count the Legs on One Segment

Centipedes and millipedes are both myriapods, and you tell them apart by the number of legs on each body segment, not the total. A centipede has one pair per segment, set out at the sides of its body, and it is a fast, venomous hunter. A millipede has two pairs on most body segments, set underneath its body, and it is a slow animal that eats rotting leaves and wood and has no venom. The total can mislead: Britain's western yellow centipede can have 166 legs, more than many millipedes. (Woodlice, by comparison, are crustaceans rather than myriapods, and adults have just seven pairs of legs.)

Frequently Asked Questions

Do centipedes have 100 legs?

No centipede species has 100 legs. That total would need 50 pairs, and every species has an odd number of pairs, so the nearest real counts are 98 legs (49 pairs) and 102 legs (51 pairs). A few abnormal individuals have turned up with an even number of pairs, such as the three with 80 pairs in the 2009 study, but we have found no record of one with exactly 50.

Why do centipedes have so many legs?

Because the trunk is a chain of segments and each leg-bearing segment carries a pair, so more segments means more legs. The soil centipedes have the most: their long, slender bodies let them wriggle between the grains of the soil. The fast house and stone centipedes stop at 15 pairs.

Which centipede has the most legs?

Gonibregmatus plurimipes, a soil centipede from Fiji, with 191 pairs (382 legs). In Britain the most is 101 pairs, in the rare Cornish Stigmatogaster souletina. More legs do not mean a bigger animal: the largest centipede, the tropical Scolopendra gigantea, grows to about 30cm on 21 or 23 pairs, while Britain's western yellow centipede, with up to 83 pairs, reaches about 7cm.

How many legs does a house centipede have?

An adult house centipede (Scutigera coleoptrata) has 15 pairs, 30 long legs in all. It hatches with 4 pairs and adds the rest as it moults. The species comes from the Mediterranean. In Britain it is usually found in heated warehouses, though it can live outdoors in the Channel Islands, so a centipede in a British garden is far more likely to be a stone centipede such as the brown centipede, which also has 15 pairs.

How many legs does a centipede have on each side?

Half its total, because each pair has one leg on each side. A house or stone centipede has 15 down each side, and the record holder has 191.

How many legs does the average centipede have?

There is no single typical number, because the count depends on the group. House and stone centipedes have 30 legs, giant centipedes and their relatives usually 42 or 46, and soil centipedes anything from 54 to 382.

Why is a centipede called a centipede?

The name comes from Latin: centi- means "hundred" and pes (pedis) means "foot". The real range, 30 to 382 legs, never lands on 100 for any species.

Do centipede legs grow back?

Yes. In the house centipede, which a 2024 study looked at closely, legs come off very easily when grabbed, and a new one can grow within a single moult cycle. Adults keep moulting, so they can replace lost legs throughout their lives. A regrown leg replaces the old one; it does not change the number of pairs.

Centipedes are fast, predatory and not beginner animals. If the many legs are what brought you here, millipedes are the slower relative: they eat rotting leaves and wood rather than live prey, and unlike centipedes they do not bite or sting.