INDIAN COBRAS: CHARACTERISTICS, BEHAVIOR, VENOM, BITES

INDIAN COBRAS

backside on an Indian cobra

Indian cobras (Naja naja) are also known as spectacled cobras, Asian cobras and or binocellate cobras. Native to India, Bangladesh, Bhutan, Nepal, Pakistan and Sri Lanka, they are a a species of cobra (Naja) in the family Elapidae of venomous snakes. The species is one of the "big four" species that are responsible for the most snakebite cases in India.

Indian cobras are favored by snake charmers and are revered in Hindu mythology and culture,. Measuring 1.2 to 1.7 meters (four to 5½ feet), they are common throughout south Asia and are responsible for a relatively large number of snake fatalities in India, in part due its fondness for rice paddies and roadside banks near villages. Even so they protected species under the Indian Wildlife Protection Act (1972).

The generic name naja is a Latinisation of the Sanskrit word nāga meaning "cobra" or “snake”. Local names for Indian cobras include: Naag in Hindi; Saanp in Urdu; Nalla pambu or Nagapambu in Tamil; Nagu-paamuin Telugu; Gokhra in Bengali; Phetigom in Assamese; Naag in Gujarati; Nagara Haavu in Kannada; Moorkkan in Malayalam; Naag in Marathi; Naya or Nagaya in Sinhalese. [Source: Wikipedia]

Indian Cobra Characteristics

Indian cobras are moderately-sized, heavy-bodied snakes. They can easily be identified by their relatively large and impressive hood, which it expands when threatened. Most adult range in length from one to 1.5 metres (3.3 to 4.9 feet) in length. Some however, especially those in Sri Lanka, may reach to lengths of 2.1 to 2.2 metres (6.9 to 7.2 feet), but this is relatively rare. [Source: Wikipedia]

The head of Indian cobras is elliptical, depressed, and very slightly distinct from the neck. The snout is short and rounded with large nostrils. The eyes are medium in size and the pupils are round. Many individuals have a hood mark located on the rear of the Indian cobra's hood. When the hood mark is present, it consists of two circular ocelli patterns connected by a curved line, which look a bit like spectacles, the source of one of the species’ common names.

Monocled cobras (N. kauthia) and Indian cobras (N. naja) look a lot alike except that their hood markings differ. Indian cobras have two spots on the back of their hood hoods while monocled cobras have only one on the rear of their hoods. In addition, monocled cobras have morphological adaptations to their fangs and mouth which allow them to accurately spit venom. Indian cobras do not have these adaptions. Monocled cobras are found mainly in Southeast Asia, east of the range of Indian cobras.

Indian Cobra Habitat and Where They Live

range of the Indian cobra

Indian cobra are native to the Indian subcontinent and can be found throughout India, Pakistan, Sri Lanka, Bangladesh, southern Nepal and parts of Bhutan. In India, they do not live at elevations over 2,000 metres (6,600 feet) and in extreme desert regions. Thus they are not dound in some parts of Kashmir and in the most arid parts of Thar desert. They may or may not occur in the state of Assam. [Source: Wikipedia]

Indian cobra range across most Pakistan, with the exception of desert areas, most of Balochistan province, parts of Khyber Pakhtunkhwa Province, and mountains in the Northern Areas. They have been documented as far west as Duki, Balochistan in Pakistan and as far east as the Tangail District in Bangladesh. They may occur in the Kabul River Valley in eastern Afghanistan. There's been at least one report of them in Bhutan.

Indian cobras are found in a wide range of habitats: dense forests, open forests, plains, agricultural lands (rice paddy fields, wheat crops), rocky terrain, wetlands, and even heavily populated areas, such as villages, city outskirts and even urban areas. The species is often found near water. Among the preferred hiding places are holes in embankments, tree hollows, termite mounds, rock piles and small mammal dens.

Indian Cobra Color and Scale Patterns

Indian cobras come in a wide range of shades, ranging from light brown to black but most individuals have distinctive pale “spectacle” markings on the back of their hoods. Their ventral scales and underside coloration can be grey, yellow, tan, brown, reddish or black. The most common visible pattern is a posteriorly convex light band at the level of the 20th to 25th ventrals. Salt-and-pepper speckles, especially in adult specimens, are seen on the dorsal scales. [Source: Wikipedia]

Indian cobra colors and patterns vary a lot depending on where they live. Those in Sri Lanka often have poorly defined banding on their back. Changes in the snake’s body color as it grows are fairly common in the northwestern parts of their geographic range — in southern Pakistan and northwestern India. In southern Pakistan, for example, juveniles may be grey in colour and lack a a hood mark while adults are uniformly black in colour on their back and lighter on the front.

Patterns on the throat and ventral scales are also variable. The majority of individuals have a light throat area followed by dark banding, which can be 4–7 ventral scales wide. Adult specimens also often exhibit a significant amount of mottling on the throat and underside, which makes patterns harder to make than on other species of cobra.

Indian Cobra Behavior and Reproduction

frontside on an Indian cobra

Indian cobras strike defensively with their mouths closed. Good swimmers and tree climbers, they are sometimes seen during the day but are most active at night. They feed on small mammals, birds, lizards and other snakes, killing them in a matter of seconds with their powerful venom. In turn, cobras are fed on by mongooses and birds of prey.

Indian cobras are oviparous and lay their eggs between the months of April and July. The female snake usually lays between 10 and 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 (8 and 12 inches) in length. The hatchlings are independent from birth and have fully functional venom glands.

Indian Cobra Venom

Indian cobra venom mainly contains a powerful post-synaptic neurotoxin and cardiotoxin that attack the nervous system and heart. The venom acts on the synaptic gaps of the nerves, paralyzing muscles. 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. [Source: Wikipedia]

In mice, the preferred LD50 value of Indian cobra venom is estimated to be 0.56 milligrams per kilogram via subcutaneous injection (SC). However, there's a wide range of potency, ranging from 0.22 milligrams per kilogram among a subspecies in (Pakistani N. naja karachiensis) to 0.84 milligrams per kilogram in some Indian specimens).

Minton (1974) reported a value of 0.29 milligrams per kilogram SC for specimens from northwest India, along with an average venom yield per bite range between 170 and 250 milligrams (dry weight). In another study, the average venom yield was 169 milligrams and a maximum yield of 610 milligrams (both were dry weights of milked venom).

The venom of young cobras is sometimes taken as a recreation drug, with snake charmers being paid for providing bites from their snakes. The affects are said to include loss of consciousness, euphoria, and sedation. This practice is now seen as outdated.

Indian Cobra Bites

The Indian cobra is one of the big four snakes of South Asia that are responsible for the majority of human deaths by snakebite in Asia. Their cobra bite can cause considerable tissue damage and sometimes paralysis. Envenomation symptoms begin between fifteen minutes and two hours following the bite. The mortality rate of bite victims is around 10 percent. In Bangladesh, Indian it is responsible for most of the snake bite cases. [Source: Wikipedia]

Indian cobra venom composition: Abbreviations: 1) VST, venom specific toxins; 2) NGF, nerve growth factor; 3) 3FT, three-finger toxins; 4) AVP, accessory venom proteins; LAAO,L-aminoacid oxidase; 5) PLA2, phospholipase 2; 6) VEGF, vascular endothelial growth factor; 7) CVF, cobra venom factor; 8) PDI, protein disulfide isomerase; 9) CRISP, cysteine-rich secretory venom proteins; 10) SVMP, snake venom metalloproteinases;

Though Indian cobras are responsible for many bites, only a small percentage are fatal if proper medical treatment and antivenom are given. Mortality rates 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 20–30 percent, but in another study involving victims who were given prompt medical treatment, the mortality rate was only 9 percent.

In a survey of snakebites in India, 91.4 percent of cases were bitten by an unidentified snake. Of the 6.1 percent of identified venomous snakes responsible for bites, 40 percent were bu Indian cobras. Local necrosis (tissue death) may occur. Severe local pain and swelling may begin almost immediately after the bite. The pain persists while swelling and tenderness extend up the bitten limb, sometimes spreading to the adjacent trunk. Early systemic symptoms include headache, nausea, vomiting, dizziness and a feeling of lassitude, drowsiness and intoxication. "Many subjects describe their drowsiness as if they had imbibed large quantities of some potent intoxicant."

Neurotoxic symptoms begin with ptosis (the patient puckers their brow, contracting the frontalis muscle, attempting to raise the eyelids or tilts the head back so as to see beneath the drooping upper lids), profuse viscid saliva, inability to clear secretions, sagging of the jaw or inability to open the mouth and progression to respiratory paralysis. Darkening of the necrotic area of skin and blistering are apparent by about the third day with a characteristic putrid smell typical of necrotic cobra bites in Africa and Asia.

Necrosis is the outstanding feature of local envenoming. Most patients were bitten on foot while working in rice fields. Health officials recommend wearing of shoes or boots while working, and say that people bitten by a snake should apply a firm binding above the bite and go to the nearest health centre or hospital.

Indian Cobra Bite Treatment

There is an antivenom for Indian cobra bites. Polyvalent serum is available and used for treating such bites. Zedoary, a local spice with a reputation for being effective against snakebite, has shown promise in experiments testing its activity against cobra venom. As of November 2016, an antivenom has been developed by the Costa Rican Clodomiro Picado Institute, and the clinical trial phase was in Sri Lanka.

The outstanding feature of systemic envenoming is paralysis of the muscles due to rapid action of neurotoxin at the myoneural junction (synapse between a motor nerve and a muscle fiber). Respiratory paralysis may occur within three to five hours in severe cases. Drowsiness is the first symptom, but it is difficult to assess because it is a subjective symptom. All of the cases developed ptosis 1.5 to 6 hours after the bite. Since ptosis is easy to detect it is a valuable clinical sign for early diagnosis of systemic envenoming due to cobra bite. Restlessness, irregular breathing, and mental confusion usually developed before respiratory paralysis, indicating that they are significant early clinical signs of impending respiratory failure. It is important for clinicians to recognize the early signs of respiratory failure.

Cases which show signs of systemic envenoming require antivenom. If some hours have elapsed since the bite the antivenom may be less successful. In general, 100 ml. of antivenom should be given in the first 30 minutes. If there is no distinct clinical improvement within 1 hour the dose should be repeated. Tracheostomy and artificial respiration are essential in cases of respiratory failure.

Image Sources: Wikimedia Commons

Text Sources: Animal Diversity Web animaldiversity.org ; National Geographic, Live Science, Natural History magazine, David Attenborough books, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The New Yorker, Time, Reuters, Associated Press, AFP, Lonely Planet Guides, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.

Last updated February 2025