Indian Cobra (Asiatic Cobra)

Indian cobra  also known as Asian cobra or spectacled cobra is a species of the genus Naja found in the Indian subcontinent and a member of the "big four", the four species which inflict the most snakebites in India. This snake is revered in Indian mythology and culture, and is often seen with snake charmers. It is now protected in India under the Indian Wildlife Protection Act (1972).

On the rear of the snake's hood are two circular ocelli patterns connected by a curved line, evoking the image of spectacles. Hindus believe them to be the footmarks of Krishna, who danced on Kāliyā, the hundred and ten hooded snake's head. An average cobra is about 1.9 meters (6 feet) in length and rarely as long as 2.4 meters (nearly 8 feet). The most distinctive and impressive characteristic of the Indian cobra is the hood, which it forms by raising the anterior portion of the body and spreading some of the ribs in its neck region when it is threatened.  The spectacle pattern on the hood varies greatly, as does the overall colour of the snake.

An additional line is seen above the spectacle in this cobra. This is just one of the many different patterns that can be found on a cobra.

The genus name Naja comes from Indian languages. The Indian cobra or spectacled cobra, being common in South Asia, is referred to by a number of local names deriving from the root of Naag (Hindi, Sanskrit, Oriya, Marathi), Moorkan (Malayalam), Naya (Sinhalese), Naagu Pamu (Telugu), Nagara Haavu (Kannada), Naaga Pambu or Nalla pambu (நாகப் பாம்பு/நல்ல பாம்பு) (Tamil) "Phetigom" (Assamese) and Gokhra (Bengali).

The Oriental ratsnake Ptyas mucosus is often mistaken for the cobra; however this snake is much longer and can easily be distinguished by the more prominent ridged appearance of its body. Other snakes that resemble Naja naja are the banded racer Argyrogena fasciolata and the Indian smooth snake Coronella brachyura.

Distribution, habitat and ecology

The Indian cobra is native to the Indian subcontinent which includes present day Nepal, Pakistan, India, Bangladesh, and Sri Lanka. It can be found in plains, jungles, open fields and the regions heavily populated by people. Its distribution ranges from sea-level up to 2,000 metres (6,600 ft) above sea-level. This species normally feed on rodents, toads, frogs, birds and other snakes. Its diet of rats leads it to areas inhabited by humans including farms and outskirts of urban areas.

Reproduction

Indian cobras are oviparous and lay their eggs between the months of April and July. The female snake usually lays between 10 to 30 eggs in rat holes or termite mounds and the eggs hatch 48 to 69 days later. The hatchlings measure between 20 and 30 centimetres (7.9 and 12 in) in length. The hatchlings are independent from birth and have fully functional venom glands.

Venom

The Indian cobra's venom mainly contains a powerful post-synaptic neurotoxin and cardiotoxin. The venom acts on the synaptic gaps of the nerves, thereby paralyzing muscles, and in severe bites leading to respiratory failure or cardiac arrest. The venom components include enzymes such as hyaluronidase that cause lysis and increase the spread of the venom. Envenomation symptoms may manifest between 15 minutes and 2 hours following the bite.

In mice, the SC LD50 range for this species is 0.45 mg/kg – 0.80 mg/kg. The average venom yield per bite is between 169 and 250 mg. Though it is responsible for many bites, only a small percentage are fatal if proper medical treatment and anti-venom are given. Mortality rate for untreated bite victims can vary from case to case, depending upon the quantity of venom delivered by the individual involved. According to one study, it is approximately 15–20%. but in another study, with 1,224 bite cases, the mortality rate was only 6.5%.

The Indian cobra is one of the Big four snakes of South Asia (mostly India) which are responsible for the majority of human deaths by snakebite in Asia. Polyvalent serum is available for treating snakebites caused by this species. Zedoary, a local spice with a reputation for being effective against snakebite, has shown promise in experiments testing its activity against cobra venom.

The venom of young cobras has been used as a substance of abuse in India, with cases of snake charmers being paid for providing bites from their snakes. Though this practice is now seen as outdated, symptoms of such abuse include loss of consciousness, euphoria, and sedation.