COBRAS: CHARACTERISTICS, VENOM, BITES, TREATMENTS

COBRAS

Indian cobra

Cobras are fast, graceful poisonous snakes that have a hood and raise the front part of their body off the ground in a distinctive way. There are about three dozen species of true cobra living by some reckoning living Africa and southern Asia. "True" belong to the genus Naja. The king cobra is venomous and has a hood, but it belongs to a different genus. There are no cobras in the Americas or east of the Wallecea line which divides Asia from eastern Indonesia, Australia and Oceania except maybe some that have been introduced there by humans

True cobras are members of the genus Naja. Naja is a genus of elapid snakes (venomous snakes with fixed fangs in the front of the upper jaw.) In the 1970s there were only six recognized cobra species: one in Asia and five in Africa and the Middle East. In the 2000s, the genus Naja had 20 to 22 species, but it has undergone several taxonomic revisions in recent years, so the number of species varies greatly depending on the source. There is wide support for a 2009 revision that merged the genera Boulengerina and Paranaja with Naja. According to that revision, the genus Naja now includes 38 species. The origin of the genus name Naja is from the Sanskrit nāga (with a hard "g") meaning "snake", which in trun is believed to be derived from Sanskrit nagna, "hairless" or "naked". [Source: Wikipedia +]

The name cobra is also applied to other genera and species that are not "true" cobras including: 1) rinkhals, ringhals or ring-necked spitting cobras (Hemachatus haemachatus) so-called for their neck band as well as its habit of rearing upwards and producing a hood when threatened; 2) king cobras or hamadryad (Ophiophagus hannah); 3) two species of tree cobras, Goldie's tree cobra (Pseudohaje goldii) and the black tree cobra (Pseudohaje nigra); 4) two species of shield-nosed cobras, the Cape coral snake (Aspidelaps lubricus) and the shield-nosed cobra (Aspidelaps scutatus); 5) two species of black desert cobras or desert black snakes, Walterinnesia aegyptia and Walterinnesia morgani, neither of which rears upwards and produces a hood when threatened; 6) the eastern coral snake or American cobra (Micrurus fulvius), which also does not rear upwards or produce a hood when threatened. 6) The false water cobra (Hydrodynastes gigas) is the only "cobra" species that is not a member of the Elapidae. It does not rear upwards, produces only a slight flattening of the neck when threatened, and is only mildly venomous. +

Websites and Resources on Snakes: Snake World snakesworld.info ; National Geographic snake pictures National Geographic ; Snake Species List snaketracks.com ; Herpetology Database artedi.nrm.se/nrmherps ; Big Snakes reptileknowledge.com ; Snake Taxonomy at Life is Short but Snakes are Long snakesarelong.blogspot.com; Websites and Resources on Animals: Animal Diversity Web animaldiversity.org ; BBC Earth bbcearth.com; A-Z-Animals.com a-z-animals.com; Live Science Animals livescience.com; Animal Info animalinfo.org ; World Wildlife Fund (WWF) worldwildlife.org the world’s largest independent conservation body; National Geographic National Geographic ; Endangered Animals (IUCN Red List of Threatened Species) iucnredlist.org

Cobra Characteristics

cobra juvenile

Generally cobra heads are elliptical, depressed, and slightly distinct from the neck with have short, rounded snout and large nostrils. The body is compressed dorsoventrally (from the back to the front) and is cylindrical or subcylindrical posteriorly. Cobras scales are smooth and strongly oblique. Different species have different scale pattersn. The eyes are moderate in size with round pupils. Long cervical ribs are capable of expanding to form a hood when threatened. Marks on the back the hoods often help distinguish one species from another. Some species have marks on their hoods; some don’t. Some have distinctive hood marks; others have marks than can vary among individuals within a species.

Cobra hoods are distended with special ribs. They generally only becomes raised when cobras are in a defensive or aggressive mood. The markings on the back of a cobra's hood are probably a defense tool. When a cobra is not disturbed its hood lies flat on its head and the cobra looks much like other snakes. A cobra has lived to the ago of 14

Cobra species vary in length and most are relatively slender-bodied snakes. The shortest one only attain a length of one meters. Most species can reach lengths of 1.84 meters (6.0 feet). The longest are about around 3.1 meters (10 feet) long, with the forest cobra described as the longest species. The longest one can rise about 80 centimeters off the ground

All cobras the characteristic ability to raise the front quarters of their bodies off the ground and flatten their necks to appear larger to a potential predator. Fang structure is variable; all species except the Indian cobra, Egyptian Cobra and Caspian cobra (Naja oxiana) can spit venom to varying degrees

Cobra Behavior and Reproduction

Cobras are generally peaceful creature who go out of the way to avoid man and will only strike when cornered. Sometimes they growl. One cobra handler told National Geographic, “Snakes aren’t evil or mean. They just want to be left alone.”

Cobras engage in mock fights before sex. The male and the female fling themselves at each other as the female attempts to rebuff the males efforts to place his body next to hers. They then strike at one another until the female adopts a submissive position and the males uses one his two penises to have sex. Copulation lasts anywhere from 2 minutes to an entire day.Cobra females lay 10 to 20 eggs, which are two inches across. The male and female take turns watching the eggs during the incubation period. Baby snakes, fully equipped with venom and fangs, are 10 inches long when they squirm out of the egg’s thin leathery shell.

Indochinese spitting cobra females lay 13 to 19 eggs 100 days after mating. Eggs hatch after 48 to 70 days depending on the temperature of incubation. Offspring are independent as soon as they have hatched. Hatchlings are anywhere from 12 to 20 centimeters long and, because they possess fully developed venom delivery systems, should be treated with the same respect as adults. Some hatchlings can be as long as 32 centimeters.

Cobras Prey and Predators

Caspian cobra

Cobras eats mice, toads and frogs. One reason the Indians are so fond of cobras is they often feed on rats, perhaps the greatest destroyer of crops on the subcontinent.Wild pigs, civets, ratels and peafowl prey on cobras. Pigs, which eat the snake as well kill it, are protected against the venom to some degree by their thick hides and layers of fat. Peafowl peck at the head of young snakes and then swallow them whole like a "string of spaghetti." Cobras are caught by hunters are sold them to snake charmers and tanneries to make wallets and handbags.

To protect themselves cobras sometimes turn their backs to predators in an attempt to intimidate them with the "bold eye" markings on the back of their hood. The extending of the hood also protects the snake by making it difficult for the teeth a predator to grip it. Some species rarely use biting for defense although they use it for hunting.

Spitting Cobras

There are around 15 species of spitting cobra out of the 33 species of true cobra in the world. Ringhals also spit. Among these species the ducts carrying the venom open onto the front rather than at the tip. By ejecting the venom forcibly they can shoot in a stream with a high degree of accuracy up to 3½ meters (12 feet). They often aim for the eyes. Poison that reaches the eyes can causes temporary — and in some cases permanent — blindness permanent if not immediately and thoroughly washed out. Spitting is used primarily as a defensive measure.

Cobra species referred to as spitting cobras have a specialized venom delivery mechanism. Their front fangs don’t eject venom downward through an elongated discharge orifice (similar to a hypodermic needle). Onstead they have a shortened, rounded opening in the front surface, which ejects the venom forward, out of the mouth. While usually referred to as "spitting", it is more like squirting. The range and accuracy of venom shooting varies from species to species. The venom has little or no effect on unbroken skin, but if it enters the eyes, it can cause a severe burning sensation. [Source: Wikipedia +]

spitting cobra

The red spitting cobra of Northern Africa is 70 to 120 centimeters (28 to 47 inches) long and ranges in color from red to gray. When threatened it can squirt venom out of small apertures in its fangs, spraying a cloud of droplets about two meters into the air. The venom does not kill but it can cause permanent blindness. Possessing a narrow hood and a red band across its neck its throat, this snake is most active at night and the early morning. Females lay up to 18 eggs in a burrow or rotting vegetation.

A recent study showed that all three spitting cobra lineages have evolved higher pain-inducing activity through increased levels of phospholipase A2 (PLA2), a group of enzymes that break down phospholipids (fatty acids that carry phosphates) in cell membranes and lipoproteins (particles made of protein and fats (lipids) that can carry cholesterol through the bloodstream to cells). This increases the pain-relieving action of the cytotoxins present in most cobra venoms. The timing of the origin of spitting in African and Asian Naja species corresponds to the separation of the human and chimpanzee evolutionary lineages in Africa and the arrival of Homo erectus in Asia. It has therefore been hypothesized that the development of our earliest human ancestors may have triggered the evolution of spitting in cobras. +

Cobra Venom

All species of cobra are capable of delivering a fatal bite to a human. Most species have strongly neurotoxic venom, which attacks the central nervous system. Death when it occurs is usually caused by respiratory paralysis. Many cobra venoms also have cytotoxic features that causes swelling and necrosis (cell death), and have a significant anticoagulant effect. Some also have cardiotoxic components to their venom that attacks the heart.

The Caspian cobra (N. oxiana) of Central Asia is the most venomous cobra species based on tests with mice and the fatality rate among humans bitten by the snakes. According to a 2019 study by Kazemi-Lomedasht et al involving mice, the murine LD50 via intravenous injection (IV) value for Naja oxiana (Iranian specimens) was estimated to be 0.14 milligrams per kilogram more potent than the sympatric Pakistani and Indus subspecies of Indian cobra karachiensis and Indian cobra indusi found in far north and northwest India and adjacent Pakistani border areas which had an LD50 value of 0.22 milligrams per kilogram. The lower the value of the LD50 the more toxic the venom is as means less venom causes more toxicity. [Source: Wikipedia]

Philippine cobra

The monocled cobras of Thailand have LD50 value of 0.2 milligrams per kilogram, while the Philippine cobra has a LD50 value of 0.18 milligrams per kilogram. The crude venom of the Caspian cobra produced the lowest known lethal dose (LCLo) of 0.005 milligrams per kilogram, the lowest among all cobra species ever recorded. Other highly venomous species are the forest cobras and water cobras of Africa. The LD50 value of the banded water cobra and Congo water cobra were 0.143 milligrams per kilogram (range of 0.131 milligrams per kilogram to 0.156 milligrams per kilogram) and 0.120 milligrams per kilogram, respectively. The Chinese cobra is also highly venomous, with a LD50 value of 0.3 milligrams per kilogram.

Antivenom is made the Queen Saovabha Memorial Institute’s snake farm in Bangkok. Venom is milked every couple of weeks and injected into horses., which develop antibodies. Horse plasma is collected and treated to make the medicine

In some cases cobra venom can be helpful. Some scientist prescribe it as a treatment for arthritis; it relieves pain but doesn't have that addictive qualities of opiates. Venom from cobras in Thailand is used by the drug company Biotherapeutics to make Immuneokine, an antiviral drug used to treat neurological disorders like multiple sclerosis, Lou Gehrig’s diseases and adrenomyeloneuropathy.

Cobra Bites

Cobras kill an estimated 10,000 people a year in India alone. They also kill large numbers of people in Vietnam, Myanmar Malaysia, and Indonesia. Often time people bitten by cobras have no reaction. Sometimes the fangs don't dig in far enough and other times, for whatever reason, snakes don't inject their venom.

Cobras have more potent toxins than vipers but vipers have longer fangs and a better system for delivering poisons deep into the victims flesh. Cobra fangs are essentially tubes (the venom-carrying grooves being enclosed by an infolding at their edges). Unlike vipers, whose long fangs fold up inside the mouth, cobra fangs are located at the front of the mouth and can be put into use more easily. Some cobras have a deep groove in the front of the teeth which allows them to spit poison.

cobra bite mark on a girl in Thailand

A cobra bite is typically described as causing sharp, immediate pain at the bite site, often accompanied by a burning sensation; this pain can quickly spread throughout the affected limb depending on the venom type and amount injected, and may be followed by swelling, redness, and other symptoms like nausea, muscle weakness, and difficulty breathing depending on the severity of the bite. [Source: Google AI]

he initial sensation is usually a sharp, piercing pain at the bite site. Many people describe a burning feeling along with the pain. Depending on the cobra species, the venom can quickly spread throughout the affected area, causing pain and swelling beyond the bite site. Cobra venom is primarily neurotoxic, which means it affects the nervous system, leading to potential symptoms like muscle weakness, paralysis, and respiratory difficulties.

Roughly 30 percent of bites by some cobra species are dry bites (a dry bite is a bite by a venomous snake that does not inject venom). Scientists have found that cobras with a higher rates of 'sham strikes' tend to be more venomous, while those with a less toxic venom tend to envenomate more frequently when attempting to bite.

Many factors influence the differences in cases of fatality. Among cobras, the cases of fatal outcome of bites in both treated and untreated victims can be quite large. For example, mortality rates among untreated cases of envenomation by the cobras as a whole group ranges from 6.5–10 percent for monocled cobras and 20–25 percent for Indian cobras to about 80 percent for Caspian cobras.

Cobra Bite Treatments

The survival rate of cobra bites among those who receive medical treatments depends on the cobra species involved. The vast majority of cobra bite victims treated make quick and complete recoveries, but some who receive similar treatment die. The most important factors in the difference of mortality rates is the severity of the bite and which cobra species caused the envenomation. Caspian cobras and Philippine cobras as we said before are the two cobra species with the most toxic venom based on LD50 studies on mice. [Source: Wikipedia]

Both Capsian and Philippine cobras cause strong damage to the nervous system and the progression to life-threatening symptoms following envenomation can be very quick. Death has been reported in as little as 30 minutes in cases involved in the Philippine cobra. The venom of the Philippine cobra is purely neurotoxic and causes minimal local tissue damage and pain. Patients respond very well to antivenom therapy if treatment is administered quickly enough.

Envenomation caused by the Caspian cobra is much more complicated as the venom contains. cytotoxins and cardiotoxins that kill tissues and affect the heart as well as neurotoxins that affect the nervous system. Victims of this snake experience severe pain, severe swelling, bruising, blistering, and tissue necrosis. Renal damage and cardiotoxicity may occur though they are rare and secondary.

Antivenom for Caspian cobras is not as effective for envenomation as it is for other Asian cobras within the same region, like the Indian cobra due to the dangerous toxicity of the venom. Massive amounts of antivenom are often required for patients. As a result, a monovalent antivenom serum is being developed by the Razi Vaccine and Serum Research Institute in Iran. Response to treatment with antivenom is generally poor among patients, so mechanical ventilation and endotracheal intubation is required. As a result, mortality among those treated for Caspian cobra envenomation is still relatively high (up to 30 percent) compared to all other species of cobra (less than one percent).

Image Sources: Wikimedia Commons, spitting cobra from the Conversation

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, CNN, BBC, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.

Last updated February 2025