Centipedes are predatory arthropods belonging to the class Chilopoda, part of the subphylum Myriapoda, a group that also includes millipedes. They are characterized by elongated, segmented bodies and many pairs of legs, allowing them to move quickly. While the name means “hundred feet,” no species possesses exactly 100 legs; the number of leg pairs always falls into an odd number range, typically from 15 to over 190. Centipedes are found globally in nearly every terrestrial environment, making them a highly successful and diverse group.
Anatomy and Classification
Centipedes share the subphylum Myriapoda with millipedes. A defining characteristic of the centipede body plan is the presence of a single pair of legs on almost every body segment, which distinguishes them from millipedes, which have two pairs of legs on most segments. Centipedes exhibit a wide range of sizes, from tiny species only a few millimeters long to massive tropical Scolopendra species that can exceed 12 inches in length.
The most unique feature is the first pair of appendages behind the head, modified into venom-injecting claws called forcipules. These forcipules are not true mouthparts but specialized front legs that curve around the head and function like a pincer. A venom gland is connected to a duct running through the forcipule, allowing the centipede to subdue its prey by injecting paralyzing toxins.
Habitat and Predatory Behavior
Centipedes are almost exclusively terrestrial and require moist microhabitats because they lack the waxy cuticle needed to retain water. They thrive in environments that offer darkness and dampness, such as under stones, within decaying logs, beneath leaf litter, and deep in the soil. This susceptibility to desiccation means centipedes are primarily nocturnal, becoming most active at night to avoid drying effects.
Centipedes are voracious carnivores, playing an important ecological role as generalist predators. Their diet consists mainly of insects, spiders, worms, and other small invertebrates, which they actively hunt down and overpower. Larger tropical species are known to prey on small vertebrates, including lizards, rodents, and snakes, using their speed and venom to quickly immobilize meals.
Centipedes and Human Health
The primary concern for humans stems from the centipede’s ability to deliver a venomous sting via their forcipules. While all centipedes possess venom, the medical significance varies dramatically depending on the species. Most species found in temperate regions, such as the common house centipede (Scutigera coleoptrata), are considered harmless to humans and pets.
The house centipede is often beneficial, preying on household pests like silverfish, cockroaches, and spiders. If a sting occurs—usually when the centipede is accidentally trapped against the skin—the effect is typically mild, causing localized pain, redness, and swelling comparable to a bee sting. In contrast, the larger Scolopendra species found in tropical and arid regions pose a greater risk, as their venom can cause intense, lasting pain, though life-threatening reactions are rare. To avoid encounters, be cautious when disturbing natural hiding places, such as turning over rocks or reaching into woodpiles without gloves.