King cobra

The king cobra, Ophiophagus hannah, is the world's longest venomous snake. An average adult is about 3.2 to 4 metres long, and the record is 5.85 metres. It lives in tropical Asia, from the Indian subcontinent through Southeast Asia to southern China, in places up to about 2,000 metres high, though it is not often seen. Despite its name it is not a true cobra: it belongs to its own genus, whose name means snake-eater.

It mostly hunts other snakes, including its own kind, and also lizards and sometimes rodents. When threatened it raises the front of its body, spreads a narrow hood and hisses. It is listed as Vulnerable on the IUCN Red List since 2010 because forests are being lost, and it is the national reptile of India. Scientists now think it may be a group of at least four species.

What it eats and how it hunts

The king cobra is an apex predator and dominates all other snakes except large pythons. It eats other snakes such as Indian cobras, banded kraits and rat snakes, and also monitor lizards. It follows the scent trails of some prey with its forked tongue, which carries smells to a sensory organ in the roof of its mouth.

After biting, it swallows the prey whole. Because of its slow metabolism, it may go for many months after a big meal without eating again. When food is scarce it takes other small animals, such as birds.

The snake that builds a nest

The king cobra is the only snake that builds a nest from dry leaf litter. The female makes it from late March to late May, usually at the base of a tree. The mound can be up to 55 cm high and 140 cm wide, with layers and one chamber for the eggs.

She lays 7 to 43 eggs, and they hatch after 66 to 105 days. Females stay near the nest for between two and 77 days, and they defend it fiercely. Hatchlings are 37.5 to 58.5 cm long, have venom as strong as adults, and may be brightly marked. A wild king cobra lives about 20 years.

Not as aggressive as its reputation

A king cobra usually avoids people and slips away when disturbed. It becomes dangerous when cornered or surprised, and people may misjudge the safe distance, because it can strike over a long range while raised. Its venom is made in large amounts and affects nerves and tissue, so a bite needs fast antivenom.

The snake has a special place in the myths and folk traditions of India, Bangladesh, Sri Lanka and Myanmar. Its biggest threats are deforestation, farmland growth, smuggling and poaching. It is protected by law in places such as India, China and Vietnam, and listed in CITES Appendix II.

On the globe

Look in the forests of southern India and Southeast Asia; the card shows the raised body and narrow hood.