Scolopendra heros

Distinguished from other North American centipedes by its exceptional size—no other native species approaches 8 inches in length. Among scolopendromorphs, the combination of large size and distinctive coloration separates it from smaller congeners. The 21 or 23 leg pairs (versus 15 in Scutigeromorpha and Lithobiomorpha) place it in Scolopendromorpha. The presence of ocelli (simple eyes) distinguishes it from eyeless Geophilomorpha. Regional color variants can cause confusion, but the overall large size and robust build are consistent identifiers.

Large, elongate centipede with 21 or 23 pairs of legs on the trunk. Average length 6.5 inches (170 mm), with wild specimens reaching 8 inches (200 mm); captivity specimens may grow larger. Body distinctly segmented with one pair of legs per segment. Head bears four small individual ocelli on each side. Coloration highly variable across range: castaneiceps variant has red head and first trunk segments with greenish-black body and yellow legs; arizonensis variant has red body with black head; other forms show brown, black, or dark green coloration with contrasting leg colors. Terminal legs may be modified and can be autotomized (shed) when threatened.

Primarily inhabits arid and semi-arid environments including Sonoran and Chihuahuan Desert regions. Also occurs in rocky woodland areas, such as dolomite glades in Arkansas and Missouri. Found in mixed-grass prairie, desert scrub, and rocky slopes. Remains underground in burrows or beneath cover objects during warm days, emerging in cloudy weather or at night. Requires access to moisture; desiccation is a significant threat in captivity.

Southwestern United States and northern Mexico. In the U.S., ranges from New Mexico and Arizona westward to Arkansas, Missouri, and Louisiana eastward. Northeastern limit in southwestern Missouri, northwestern Oklahoma, and Arkansas. Mexican distribution includes northern states adjacent to the U.S. border.

Active year-round in warmer portions of range; activity peaks during warmer months. Nocturnal, with surface activity concentrated at night. Emerges from underground retreats during cloudy weather regardless of season.

Carnivorous predator feeding on invertebrates and small vertebrates. Prey includes insects (crickets, grasshoppers, flying insects snatched from air), spiders, scorpions, rodents, reptiles, and amphibians. In captivity, accepts large insect larvae (Manduca), frozen/thawed mice, and pinky rats. Venom used to subdue prey rapidly—rodents may succumb within seconds of envenomation.

Hatches from eggs. Development through multiple instars with molting of exoskeleton; segment number remains constant throughout life (anamorphic development not occurring in this order). Slow-growing species with lifespan exceeding one decade in captivity. Sexual maturity reached after multiple years and molts. Detailed egg-laying behavior and early instar ecology poorly documented.

Nocturnal predator that hunts actively on the surface at night. Capable of rapid, fluid movement; strikes quickly to seize prey. When threatened, prefers flight over fight; will attempt to escape rapidly. Bites only when handled or cornered. Can climb vertical surfaces and navigate varied terrain. In captivity, exhibits persistent escape behavior and can chew through inadequate containers including Ziploc bags. Becomes lethargic at low temperatures.

Apex invertebrate predator in many arid and semi-arid ecosystems. Controls populations of insects, other arthropods, and small vertebrates. Serves as prey for larger vertebrates despite aposematic coloration and defensive venom. Contributes to nutrient cycling through predation and carcass processing.

Bites cause intense local pain, swelling, and occasional systemic symptoms including nausea, headache, and localized skin necrosis. No confirmed human fatalities attributed to this species, though severe symptoms including rhabdomyolysis and cardiac effects have been reported from Scolopendra bites generally. Popular in live displays and pet trade due to impressive size and coloration; captive care requires secure containment and humidity management. Occasionally enters buildings accidentally, causing alarm but not establishing indoor populations.

• Scolopendra giganteaSouth American congener reaching 12 inches; not naturally sympatric but may be confused in pet trade or general reference. Larger maximum size and tropical distribution distinguish it.
• Scolopendra polymorphaSmaller North American congener with more uniform coloration; typically under 4 inches, lacking the striking red/black or red/yellow contrast of S. heros.
• Scolopendra viridisSmaller southwestern species with greenish coloration; distinguished by smaller size and different habitat preferences.
• Scutigera coleoptrataHouse centipede with 15 leg pairs, compound eyes, and much smaller size; harmless to humans and synanthropic.

Claims of 2-foot specimens are demonstrably false; maximum documented size is approximately 8 inches in wild specimens, with unverified reports of 10-11 inches in exceptional captivity specimens. The invalid name 'Scolopendra Caribiaenensis' has been propagated by livestock dealers, likely referring to S. gigantea. Despite fearsome appearance and painful bite, the species is not aggressive toward humans and avoids confrontation when possible.

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• North America’s largest centipede | Beetles In The Bush
• North America’s largest centipede | Beetles In The Bush
• Recyclers of the rainforest: Bornean myriapods, millipedes (Diplopoda), and their nemesis, giant centipedes (Chilipoda) — Bug of the Week