Centipedes have a rounded or flattened head, bearing a pair of antennae at the forward margin. They have a pair of elongated mandibles, and two pairs of maxillae. The first pair of maxillae form the lower lip, and bear short palps. The first pair of limbs stretch forward from the body to cover the remainder of the mouth. These limbs, or maxillipeds, end in sharp claws and include venom glands that help the animal to kill or paralyze its prey.
Many species of centipedes lack eyes, but some possess a variable number of ocelli, which are sometimes clustered together to form true compound eyes. However, these eyes are only capable of discerning light and dark, and have no true vision. In some species, the first pair of legs at the head end of the centipede acts as sense organs similar to antennae, but unlike the antennae of most other animals, theirs point backwards. Unusual sense organs found in some groups are the organs of Tömösváry. These are located at the base of the antennae, and consist of a disc-like structure with a central pore surrounded by sensory cells. They are probably used for sensing vibrations, and may even provide a sense of hearing.
Forcipules are a unique feature found only in centipedes and in no other arthropods. The forcipules are modifications of the first pair of legs, forming a pincer-like appendage always found just behind the head.Forcipules are not true mouthparts, although they are used in the capture of prey items, injecting venom and holding onto captured prey. Venom glands run through a tube almost to the tip of each forcipule.
Behind the head, the body consists of 15 or more segments. Most of the segments bear a single pair of legs, with the maxillipeds projecting forward from the first body segment, and the final two segments being small and legless. Each pair of legs is slightly longer than the pair immediately in front of it, ensuring that they do not overlap, so reducing the chance that they will collide with each other while moving swiftly. In extreme cases, the last pair of legs may be twice the length of the first pair. The final segment bears a telson and includes the openings of the reproductive organs.
As predators, centipedes mainly use their antennae to seek out their prey. The digestive tract forms a simple tube, with digestive glands attached to the mouthparts. Like insects, centipedes breathe through a tracheal system, typically with a single opening, or spiracle, on each body segment. They excrete waste through a single pair of malpighian tubules.
Their size can range from a few millimeters in the smaller lithobiomorphs and geophilomorphs to about 30 cm (12 in) in the largest scolopendromorphs.They normally have a drab coloration combining shades of brown and red.
Centipedes have a wide geographical range, even reaching beyond the Arctic Circle. They are found in an array of terrestrial habitats from tropical rainforests to deserts.
Centipedes are active hunters. They roam around looking for small animals to bite and eat. They eat insects, spiders, and other small invertebrates.
Most centipedes are active at night. During the day they seek shelter under objects on the ground, inside logs and stumps, or in animal burrows. During the hot dry weather they will usually bury themselves deep in the soil. They are not territorial and move about the environment in search of food and mates.
Centipedes live alone until they are ready to mate or when they are raising their young. When they do meet, they are often very aggressive toward one another and will sometimes eat the other. Some species living along the seashore hunt in packs. Several individuals will feed together on the same animal.
When threatened, centipedes protect themselves by running away or biting. Others whip their bodies about or spread their hind legs wide in a threatening manner.Others release bad smelling and tasting chemicals from glands on their undersides.A few centipedes produce glue that hardens within seconds when exposed to air. This sticky stuff can tangle up the legs of even the largest insect predators.
Centipede reproduction does not involve copulation. Males deposit a spermatophore for the female to take up. In one clade, this spermatophore is deposited in a web, and the male undertakes a courtship dance to encourage the female to engulf his sperm. In other cases, the males just leave them for the females to find. In temperate areas, egg laying occurs in spring and summer, but in subtropical and tropical areas, little seasonality to centipede breeding is apparent. A few species of parthenogenetic centipedes are known.
Some species of centipedes lay their eggs one at a time. In other species the female digs out chambers in rotten wood or soil and lays up to eighty or more eggs all at once. She wraps her body around her eggs and cleans them constantly so funguses, molds, or hungry predators do not harm them. Of these species some will eventually camouflage the eggs with bits of soil and abandon them. Others will remain with their eggs, even until after they hatch. They are unable to hunt and remain with their mother until after their next molt, or shedding of their hard outer coverings or exoskeletons.
The common house centipede can live for more than a year, while other species have been known to live for as long as 5-6 years.
Centipedes are fascinating pets for advanced hobbyists. However, they are not pets to be handled, rather they are visual pets enjoyed for their interesting appearance and behaviors. Although they are not considered aggressive towards humans, centipedes to not like to be cornered or touched and will respond defensively in such situations.
Centipedes do not sting, but have a pair of poison claws behind the head and use the poison to paralyze their prey, usually small insects. Though it is reported in some places on-line that the jaws of centipedes are weak and can rarely penetrate human skin, most of the larger specimens being sold as pets can indeed give a very painful bite (or pinch). Careless individuals who are bitten can expect fairly intense pain, swelling, and a throbbing sensation. Depending on the species, this pain will last from an hour to several hours.
Though fascinating to watch, centipedes should be carefully manipulated with snake handling tools, paint brushes, and thick gloves, rather than handed. Centipedes are unlike most invertebrate pets being kept in captivity. They should be kept similarly to venomous snakes with a secure enclosure system. Once they are established in a secure enclosure and once some experience is gained in their care and daily husbandry, centipedes can provide hours of fascination.