Overview

The king cobra (Ophiophagus hannah), also called the hamadryad, is a large elapid snake native to South and Southeast Asia. It holds the distinction of being the longest venomous snake in the world, with exceptional individuals reported to reach about 5.5 m (18 ft), though most adults are considerably shorter (< 4 m). Its scientific name, Ophiophagus, means "snake eater" and reflects a diet that is largely composed of other snakes. For a general note on its size and status see size and records.

Physical characteristics and behaviour

King cobras have an elongated head, unmistakable hood when threatened, and keeled scales giving a somewhat rigid appearance. They can raise the anterior portion of their body off the ground and spread their hood to appear larger; in the tallest displays they can lift enough of their body to look a human in the face. Their senses combine good vision with a strong reliance on chemical cues detected by the tongue and Jacobson's organ. Typical behaviour is wary and reclusive — they generally avoid confrontation with people and will retreat if given an escape route (human encounters).

Diet and feeding

True to the genus name, king cobras are primarily ophiophagous: they feed mainly on other snakes, including both venomous and non‑venomous species. They will also take lizards, small mammals, and occasionally eggs. Because a single meal can be large relative to body size, individuals may fast for weeks or months between meals. Their hunting relies on stalking, striking, and overpowering prey rather than constriction.

Reproduction and lifecycle

Unlike most snakes, the female king cobra constructs a nest of vegetation in which she lays and incubates her eggs, and she remains nearby to guard the nest until the young hatch. Hatchlings are independent from birth. Lifespan in the wild is not precisely known; in captivity they may live for up to around 20 years. For more on reproductive habits see behavior and breeding.

Venom, medical importance, and predators

King cobra venom is potently neurotoxic and can cause severe systemic effects in bitten humans; rapid medical treatment and the availability of appropriate antivenom are important for effective care. Fatalities have occurred historically where access to medical treatment was limited. Natural predators are few; the Indian grey mongoose is reported as one of the species that will attack or harry cobras (mongoose interactions). Research and clinical resources on venom and treatment are available in specialist literature and regional health guidance (venom and treatment).

Distribution, habitat and conservation

King cobras are found across much of the Indian subcontinent and throughout parts of Southeast and East Asia, favoring tall rainforest, bamboo thickets, and areas near streams and lakes where prey is abundant. They are threatened by habitat destruction, fragmentation, and persecution. Conservation assessments indicate population declines in some regions; protection measures and habitat preservation are important for their long‑term survival. For regional range maps and status information see distribution and conservation reports (status).

Notable facts

  • Common name "hamadryad" links the species culturally to forest nymphs and myth.
  • They are among the few snakes that build nests and exhibit maternal care for eggs.
  • Despite their reputation, king cobras exhibit avoidance behavior and will not generally seek out humans as prey.

For further reading and field identification, consult regional field guides and specialist accounts that cover behavior, venom management, and conservation actions (human‑wildlife coexistence, regional guides, clinical resources).