King cobras are one of the most feared snakes in the world. These huge, cannibalistic snakes dwell in the rainforests of Asia. Their venom is highly dangerous, and most bites are fatal if untreated.
King cobras are the largest venomous snakes, with the longest ever specimen reaching 19 feet. Their venom is neurotoxic, meaning that it kills brain cells, and can cause paralysis. King cobras feed on snakes and lizards – their scientific name (Ophiophagus) means serpent-eater. When threatened, a king cobra will growl, rear up, and extend its fearsome hood.
Contrary to popular belief, king cobras are usually shy and non-aggressive. Bites are rare, and the majority occur when the snake is provoked. Unfortunately, king cobras are vulnerable in the wild and may soon become endangered.
Interesting Facts about King Cobras
King cobras are large, venomous snakes native to South and Southeast Asia. They are found in certain parts of India and China, and throughout every country between Myanmar and Indonesia. They live in primarily rainforest habitats, and avoid interaction with humans where possible.
Here are some fun facts about king cobras that you may not know. We’ll cover everything from their unusual behavior to their deadly venom.
1) Not True Cobras
Most of the world’s cobras are contained within the genus Naja. This includes Indian cobras, monocled cobras, water cobras, and spitting cobras among others. When king cobras were first discovered, they were thought to belong to the same genus.
However, it was soon established that king cobras are not true cobras, as they are too biologically different. They were instead recognized as belonging to their own genus, and named Ophiophagus hannah. A genetic study, conducted in 2000, found that king cobras are more closely related to mambas than true cobras.
King cobras belong to the same taxonomical family as North American coral snakes (Elapidae). Like coral snakes, king cobras have smooth scales and round pupils, differentiating them from vipers such as rattlesnakes.
2) Eat Other Snakes
King cobras are deemed ‘kings’ for the same reason that North American kingsnakes are so called. They are ophiophages, meaning that they eat other snakes. This is also the reason that the king cobra’s scientific name is Ophiophagus.
North American kingsnakes eat a variety of other animals, such as mammals and birds, as well as snakes. But king cobras almost exclusively prey on their own kind. Some of their favorite species include:
- Indian cobras
- Rat snakes
- Keelback snakes
- Pit vipers
- Other king cobras
If the opportunity presents itself, they may also eat other reptiles, such as lizards. Adult king cobras can survive for months without food after eating a particularly large meal.
3) Biggest Venomous Snake in the World
Most types of venomous snakes are smaller than non-venomous snakes. The biggest snakes in the world, including reticulated pythons, Burmese pythons, and green anacondas, are all non-venomous. Non-venomous snakes need to be large in order to overpower and constrict their prey. Venomous snakes merely need to strike once and back away.
The exception to this rule is the king cobra. Reaching up to 18 feet long, king cobras are the largest venomous snakes in the world. Their average length is 10 to 13 feet long. Like all snakes, they continue growing for as long as they live.
The longest individual king cobra ever found in the world was 19 feet long. Their vast size allows king cobras to swallow almost any species of snake, including reticulated pythons.
4) Growl When Threatened
The hiss of a snake is usually high-pitched (around 7,500 Hz). But king cobras are an exception to this. They have a very low-pitched, deep hiss, with a dominant frequency of around 600 Hz. This has been coined the king cobra ‘growl’.
The king cobra growl is a startling noise, and does a great job at dissuading predators from attacking. It may also be one of the only hisses that other snakes can hear. Snakes’ hearing is limited to low-frequency sounds and ground-borne vibrations.
According to the Journal of Experimental Zoology, the secret to the king cobra growl is the shape of its trachea. In a king cobra’s windpipe, there are hollow cavities called tracheal diverticula. These gaps act like resonating chambers. When the snake hisses, the sound reverberates around these chambers, causing a loud, low growl.
5) Build Nests for Their Young
Snakes are not famous for being caring creatures; they don’t have much maternal instinct. Most species of oviparous (egg-laying) snakes will abandon their eggs immediately after laying. Newly-hatched snakes can look after themselves, and don’t need their mother’s care.
However, king cobras show a surprising amount of care for their young. When a female king cobra is gravid (pregnant), she will begin building a large nest out of sticks and bamboo leaves. These nests are up to 4 feet wide and tall.
The snake will lay her eggs in the center (up to 50 per clutch), and fiercely guard them. She acts as a protector against predators who want to eat the eggs, and clumsy animals that may step on them. When the eggs are nearly ready to hatch, she’ll leave and never return.
6) Do Not Spit Venom
A common misconception is that king cobras spit venom. This isn’t true. There are several types of spitting cobras, but king cobras aren’t among them. Examples of cobras that do spit venom include red spitting cobras and rinkhals (ring-necked spitting cobras).
Spitting cobras have tiny, forward-facing holes near the tips of their fangs. When threatened, they squeeze their venom glands to force a stream of venom out of this hole.
King cobras, however, don’t have this mechanism. They have short fangs, mostly covered in a protective sheath. The long, narrow hole at the tip is designed for injecting venom directly into their victim’s body.
When a king cobra attacks, it strikes at the base of its target’s head. It then holds on for several minutes, to inject as much venom as possible.
7) Venom is Neurotoxic
Like most snakes in the Elapidae family, king cobras have extremely potent venom. The amount of venom delivered in one single bite is enough to kill 20 people.
What makes a king cobra’s venom so deadly is its neurotoxic properties. A neurotoxin is a type of poison that specifically affects the nervous system (brain and spinal cord). It interferes with synaptic function, and kills brain cells. Symptoms include:
- Extreme pain
- Blurred vision
- Respiratory difficulties
- Cardiovascular failure
These symptoms could vary depending on how much venom was injected, treatment received, and where the snake was from. According to Acta Tropica, king cobras from Indonesia and China have deadlier venom than those from Malaysia and Thailand.
8) Surprisingly Shy
As king cobras are the largest venomous snake in the world, you may assume them to be aggressive. But this is far from the truth. King cobras are famously shy, and prefer to flee dangerous situations rather than attack.
If you encountered a king cobra in the wild, it wouldn’t bite you unless it felt that you were putting its life in danger. It may rear up onto its tail, spread its hood, and growl as a threat display. But it would try its hardest to escape before it resorted to striking.
That being said, female king cobras are highly defensive over their eggs. A nesting mother is far more likely to act aggressively or defensively when confronted with a potential predator.
9) You Can’t Always See a King Cobra’s Hood
When you imagine a king cobra, you’ll most likely picture a wide ‘hood’ of skin on either side of the neck. This is what all cobras are famed for. However, what you may not know is that a cobra’s hood isn’t always visible.
Most of the time, when king cobras are hunting or resting, they have no hood at all. They extend it voluntarily, as a type of threat display, when they feel that they’re in danger. The hood, combined with the defensive posture (raised off the ground), makes the snake appear bigger than it is.
According to the Journal of Experimental Biology, king cobras use muscles attached to their ribs to hold the hood erect. They don’t hold it open permanently, as this would exert too much energy.
10) Can Swim and Climb Trees
King cobras are considered terrestrial snakes. They spend most of their time at ground-level, slithering along the forest floor.
However, for a terrestrial species, king cobras are surprisingly adept at traversing different habitats. They are fantastic swimmers, and can swim across streams, rivers, ponds and lakes. They glide along the surface of the water, and can hold their breath for several minutes if necessary.
King cobras can also climb trees. They may do this if necessary to catch tree-dwelling snakes and lizards to eat. This behavior is how the king cobra earned the second part of its species name, Ophiophagus hannah. The word ‘hannah’ comes from ‘hamadryad’, a tree-dwelling wood nymph in Greek mythology.
11) Humans are King Cobras’ Main Predators
Unsurprisingly, few animals hunt and eat king cobras – at least once they’ve reached adulthood. This is due to their vast size and their dangerous venom. Mongooses are immune to cobra venom, but normally feed on smaller species, such as the Indian cobra.
Humans are the biggest threats to king cobras. King cobras are regularly hunted and killed by people in Southeast Asia, for a variety of reasons:
- The skin is used for clothing, bags, shoes, and accessories.
- King cobra meat (muscle tissue and fat) is used as food.
- Various parts of the snake, such as the skin and gallbladder, are used in traditional Chinese medicine.
King cobras are also killed to sell ‘cobra pearls’. These are small stones sold as snakebite cures, and supposedly taken from the snake’s head. However, they are not real. Sellers will insert stones into dead cobras’ heads before extracting them in front of a potential buyer.
12) Up to 60% of King Cobra Bites are Fatal
Because king cobras are non-aggressive, they rarely bite humans unless seriously provoked. But if you are ever bitten by a king cobra, the outlook isn’t good.
According to an estimate by the University of Adelaide, around 50-60% of untreated king cobra bites are fatal. The rate of envenoming is over 80%, meaning that “dry bites” are uncommon. When a king cobra bites, it will hang on for several minutes, injecting as much venom as possible.
There is a type of antivenom available that is effective against king cobra venom. However, not all hospitals in Southeast Asia carry it. And as most bites occur in sparsely populated areas, people can’t always get treatment in time. Fortunately, king cobra bites are quite rare.
13) Males Wrestle for Dominance
King cobras are usually solitary creatures. But towards the end of the dry season (January to March), they go looking for a mate. And if two males encounter each other, they will fight each other for the right to breed.
But as king cobras lack limbs, the only way to prove their dominance is to wrestle. The snakes will rear up in the air and push at each other’s’ bodies. Each king cobra will attempt to force the other one onto the ground.
Whichever snake comes out victorious is permitted to mate with the female. He will mate with the same female year after year, provided he wins the wrestling match.
14) Baby King Cobras Are Brightly Colored
Juvenile king cobras are small, but highly distinctive and easy to spot. Their dorsal side is black, with brightly colored chevrons that can be yellow, buff or white. Their ventral side (belly) is cream with thick black stripes.
But this vivid coloration is lost as the king cobra ages. Over the first few years of life, these markings slowly fade. Adult king cobras are tan, brown, or olive green, with little patterning.
The babies’ bright chevrons are an example of aposematism. This is a type of defense mechanism that warns predators to stay away. As the cobra gets larger and less at risk of predation, it takes on a more natural color. This helps it to stay camouflaged and sneak up on prey.
15) Used in Snake-Charming
King cobras are one of the species used in Indian snake charming. Other types of snakes used include Indian cobras (Naja naja) and Egyptian cobras in Northern Africa (Naja haje).
Snake charmers capture wild king cobras, and train them to respond to a wind instrument called a pungi. The snakes can’t hear the music, as they can only hear low frequencies. They respond instead to visual cues, which cause them to rear up and expand their hood.
To prevent bites, many snake charmers sew the cobra’s mouth closed. They may also remove their venom glands, or starve them so that they are too weak to attack. Still, not all bites can be avoided. A study in the Quarterly Journal of Medicine reports three snake charmers bitten by king cobras in Myanmar.
16) Will Soon Be Endangered
King cobra populations are far from abundant in the wild. According to the IUCN Red List of threatened species, king cobras are classified as vulnerable worldwide.
In certain areas, such as Vietnam and China, they are already endangered. There are several factors contributing to this:
- Habitat loss due to deforestation.
- Poaching. King cobras are hunted for use in snake charming, food, clothing, and medicine.
- Fear. When encountered accidentally, people often kill king cobras out of fear. This is especially likely when snakes enter villages or properties.
In some Asian countries, there are conservation measures in place. For example, in India, killing a king cobra is punishable by up to 6 years in jail. But unfortunately, king cobra populations worldwide are decreasing every year.
17) Can Live for 30 Years
While their populations may be on the decline, individual king cobras can live for a surprisingly long time. Wild specimens can purportedly survive for as long as 30 years, though the average life expectancy is 15-20.
For a snake, this longevity is impressive. Many species of snakes don’t live longer than 10 years in the wild. But owing to king cobras’ substantial size and powerful venom, they have few natural predators. Once they reach adulthood, these snakes are usually left alone.
It’s possible that king cobras may live even longer in captivity. However, there’s not much data on this, as few people keep king cobras as pets. They are not only dangerous, but extremely difficult to feed and care for.