by Annette J Beveridge
Few snakes strike fear into the heart as much as the king cobra (Ophiophagus hannah). Found in jungles in southern and south-east Asia, the King Cobra is the longest venomous snake in the world with an average length of 10-13 ft (3 -4 metres). The largest recorded king cobra was discovered in Thailand and reached 18ft 4 inches.
Capable of lifting 1/3 of its body off the ground, the king cobra moves from side to side in a threatening pose. With black, penetrating eyes, they are identifiable by the hood that flares outwards when the snake feels threatened. The hood is actually the ribs and muscles.
A group of king cobras is called a quiver
These are smooth snakes with a yellow, brown, green and black scaly pattern. On the back of the neck, there is a distinctive pattern of colour. Some king cobras are leucistic, and this is where much of the colouration is missing due to a partial loss of pigmentation. The snake may have white or patchy colouring.
These snakes are primarily killers of other snakes and lizards and will take rat snakes, green whip snake, pit vipers, kraits, pythons, and other cobras as a primary food source. If food becomes scarce, they will feed on small vertebrates. Once the snake has eaten well, it will not need to eat again for months due to a slow metabolic rate. King cobras have been known to constrict prey but this is not typical.
The name comes from the Greek word meaning snake eater.
The forked tongue receives chemical information which is transferred to the Jacobson’s organ located at the top of the mouth. This is a sensory receptor. To identify the location of prey, the tongue flicks out detecting movement as well as vibrations. This sensory organ is remarkable as it can monitor the presence of prey up to 330 ft away. Prey, once caught, is swallowed whole easily due to its flexible jaws.
The venom is deadly but they are not typically aggressive and are much more likely to try to escape confrontation. .
King cobras are found in dense forests, the foothills of the Himalayas, mangrove forests, and even on coastlines. They prefer areas with a water source as this means more prey species are available. The breeding season begins in January and ends in April. Males will wrestle with other males to mate with a female and the strongest male wins. A king cobra will push at the female with its head and this demonstrates a sign of interest. King cobras are solitary and monogamous and will breed with the same female the following year.
Males are larger than females – this is known as sexual dimorphism which is unusual.
Unlike most snakes, the female king cobra is relatively caring creating a nest made from dry leaf litter in late March through to late May. These are usually located at the base of trees and will have several layers to them. The nests can reach up to 4 feet wide and in height. Approximately 7 – 43 eggs are laid in the centre. The incubation period is between 66 -105 days and the females guard the eggs aggressively during this time.
The young snakes, known as hatchlings, are capable of hunting and using their venom from the moment they emerge. Their venom is potent but the toxicity decreases as the snakes get older. This is because the venom sacs have greater capacity to hold venom as the snake matures. The hatchlings are brightly coloured which sends a warning to predators. Their colouring alters as they grow, turning green, black and dark brown.
King cobras have excellent eyesight and are able to detect movement 100 metres away but sense ground vibrations rather than hearing the noise around them. Their fangs are impressive – approximately 1/2 an inch in length and are fixed to the upper jaw so they cannot grow longer or they would penetrate the floor of the mouth. They angle backwards and can be used to draw the prey towards the stomach.
While the venom is not the most potent, the neurotoxins would be enough to kill 20 people or to kill an elephant.
When cobras hiss, the sound is produced by tiny holes in the trachea and the lungs resonate the sound. It can sound like a low rumble or a dog growling rather than a hiss. It is pitched at around 600 Hz different to the hiss of most snakes at 7,500 Hz. Other snakes may be able to hear this sound as low-frequency sounds or vibrations at ground level can be felt or heard. In the windpipe, there are hollow cavities that work as resonating chambers. These cavities are known as tracheal diverticula.
If the snake is provoked, it can strike from a long range. The bite can be sustained and a large quantity of venom can be delivered via glands attached to hollow fangs. Venom is forced through by the flexing of a small muscle. The venom is neurotoxic, causing paralysis affecting the nervous system – the brain and spinal cord. The instinctive impulse to breathe is also targeted.
Symptoms include:
- Extreme pain
- Paralysis
- Respiratory difficulties
- Blurred vision
- Drowsiness
- Cardiovascular failure
The king cobra belongs to its own genus and is more closely related to mambas.
These snakes live for approximately 20 years but logging and habitat destruction increases pressure on the species. Sadly, with a natural fear and distrust of these snakes, despite being protected, they can be killed if they come into conflict with locals.
