The name “millipede” instantly suggests a count of a thousand legs, a number that seems almost unbelievable for a single creature. The literal translation of the name sets up a major biological question, but the actual number of limbs on most species is far less dramatic than the name implies.
The Truth Behind the Name
The term “millipede” originates from the Latin words mille, meaning “thousand,” and pes, meaning “foot.” This naming convention was never intended to be a precise count but rather an exaggeration to convey the sheer number of legs the creature possesses. It functions similarly to the word “centipede,” which translates to “hundred feet” but whose species do not actually have exactly 100 legs. For the vast majority of the approximately 12,000 known millipede species, the leg count falls into a range between 34 and 400 limbs.
Before a recent discovery, the answer to the question in the title was a definitive “no,” with the record holder falling short of the thousand-leg mark. The previous record was held by the species Illacme plenipes, with the leggiest specimen recorded having 750 legs. However, a scientific discovery in 2020 changed the landscape completely, proving that the thousand-foot name is now technically possible for at least one species.
Anatomy and Leg Count
The reason millipedes can achieve such high limb counts is due to a unique anatomical feature called a diplosegment. The class name for millipedes, Diplopoda, literally means “double foot,” which directly references this structure. Most of the millipede’s body trunk is composed of these fused segments, where two embryonic segments merge into one apparent ring.
Each resulting diplosegment carries two pairs of legs, totaling four legs for every visible body ring after the first few segments near the head. Their legs are positioned underneath their round, cylindrical bodies, which aids in pushing through soil and leaf litter as they move.
This distinct anatomy allowed for the discovery of the first known animal to truly surpass the thousand-leg mark. The species Eumillipes persephone, found deep underground in Western Australia, can possess up to 1,306 legs, making it the leggiest animal on Earth. This eyeless, pale creature lives in darkness and proves that the ancient common name was, in fact, an attainable number for one species.
Millipedes vs. Centipedes
The public often confuses millipedes with centipedes, but the two are distinct creatures with different characteristics and behaviors. The most straightforward way to tell them apart is by observing the legs on each segment: millipedes have two pairs of legs per segment, while centipedes, belonging to the class Chilopoda, have only one pair of legs per segment. Millipedes also have a more rigid, rounded, and cylindrical body shape, optimized for pushing and burrowing through dense organic matter.
Centipedes, conversely, possess a flatter, more elongated body that allows for greater flexibility and speed. This difference in body design reflects their contrasting lifestyles. Millipedes are slow-moving detritivores, meaning they feed on decaying plant material like rotting wood and leaves. They are harmless to humans and often curl into a tight coil when threatened, sometimes releasing a foul-smelling liquid as a defense mechanism.
Centipedes, on the other hand, are fast-moving, agile predators that actively hunt other small arthropods and insects. They use their first pair of legs, called forcipules, which are modified into venomous claws, to inject venom into their prey. Their predatory nature contrasts sharply with the millipede’s role as a decomposer, which contributes significantly to soil health and nutrient cycling in ecosystems.