Active by day, the agile king cobra is capable of moving swiftly along the ground and through trees or water while searching for prey (2) (4). This species’ diet consists almost exclusively of snakes, the majority of which are non-venomous species, such as small pythons and rat snakes, although highly venomous species, such as cobras, kraits and even other king cobras, are also taken (7). The king cobra is also known to feed upon monitor lizards and take eggs on occasion (7) (8). Prey is located by smell and sight, and is actively pursued. When in range, its victim is dispatched with a rapid strike, injecting a large quantity of venom, which affects the nervous system and causes respiratory failure (2) (7).
While the king cobra’s venom is not as toxic as that of some highly venomous species, the sheer volume produced in a single bite is enough to kill 20 to 30 adult humans or a fully-grown Asian elephant (3) (8). Nevertheless, as this species is generally non-aggressive and occupies deep forest, bites to humans and the resulting fatalities are rare (2).
In response to threats, when unable to escape, the king cobra gives a dramatic display, in which the front third of the body is lifted off the ground, reaching a height of up to 1.5 metres. The narrow hood is also erected, a growling hiss is produced, and downward strikes are made, although it rarely attempts to bite (4) (9).
From January to March male king cobras seek out a mate by following chemical pheromone signals released by the females. Once located, the male employs courtship behaviours such as rubbing the head along the female’s body, which may develop into butting and nudging actions if the female shows reticence to mate. If other males are present, they may compete for the female by wrestling and attempting to push each other's head to the ground. During mating the male and the female’s bodies intertwine, and remain in this position for several hours (7).
The female produces a clutch of 20 to 50 eggs, which are laid in April, May or June, and deposited within a nest of twigs, leaves and other vegetation. The nest comprises a lower chamber for the eggs, which is covered over with leaf-litter, and an upper chamber on top, in which the female resides, guarding the eggs from predators and trampling. Such a complex nest is unique among snakes, and is considered to be a sign that the king cobra may be one of the most intelligent snake species (7). The eggs, which are incubated by the heat of the rotting vegetation, take between 60 and 90 days to hatch, and just prior to hatching the female abandons the nest, ceasing all parental care (7) (9).
The newborn cobras measure around 35 centimetres at birth, and already possess venom as toxic as the adult’s. Nevertheless, they are preyed upon by civets, mongooses, giant centipedes and army ants until they are several months old (7).