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Armed And Dangerous... Naturally

Armed And Dangerous... Naturally

Venom. Poison. Toxin. Words often interchanged, used inconsistently and with much ambiguity. Though the underlying structure and disposition of poisons and venoms is common, they differ in the manner they are delivered. An animal or plant is labelled poisonous if it is capable of causing harm when touched or ingested. A venomous animal, on the other hand, infuses its prey or attacker with venom through an application, bite or sting. Natural toxins are poisons produced by plants or animals as a means of defence, or offence.

Within the animal kingdom, certain snakes, jellyfish, fish, spiders, scorpions, centipedes, bees, cone snails, newts, frogs, platypus and even a primate, the slow loris, are endowed with poisons in their bodies. Poisons are protein molecules, highly complex in structure, and shaped to neatly and precisely lock onto specific proteins in the target cells of animals – such as neurons, impacting the nervous system to paralyse the victim or blood cells, affecting the circulatory systeto prevent clotting or degradation of muscle cells.

How did poisons and their sophisticated delivery systems evolve? Some evolutionary biologists suggest that toxins or poisons may not always have existed in nature. The genes responsible for producing them originally, probably had other functions. For instance, as digestive enzymes. It is speculated, that the genes mutated to make extra copies and these extra copies might have eventually gone on to mutate and duplicate freely and rampantly, while the original genes remained unaffected. The copies gave random signals of where they should manifest themselves in the form of proteins – In some newts and frogs, the skin; in snakes, the venom glands and, in scorpions, the sting became the respective ‘poison points’. Natural selection then completed the job to ensure that the newly-derived traits triumphed. As the task of killing prey became more efficient, the traits evolved to become more potent and sophisticated. And if you thought it was only animals that managed to turn toxins to their offensive and defensive advantage, think again! Plants and fungi evolved more sophisticated deterrents to discourage herbivores from feeding on them.

Interestingly, as poisons got more potent, so did resistance in potential ‘victims’. When a caterpillar develops resistance to a particular toxic plant, it will end up with more food options that are denied to less-fortified competitors. These advantages will be passed on through genes to its progeny, which will be able to consume the poisonous plants without harm. As plants get more toxic, the caterpillar’s resistance is enhanced. It’s a constant race to stay one step ahead. This is co-evolution. This is life.

KING COBRA Ophiophagus hannah

LOCATION: Coorg, Karnataka

Photo: Bishan Monnappa.

The king cobra’s bite packs a seriously fatal punch. It seems like overkill that an animal this large (it can grow up to five-and-a-half metres) also happens to be among the most venomous animals on the planet. This limbless reptile possesses a neurotoxic venom, which damages the nervous system of its victim. The venom, a biological protein-cocktail, targets the neurotransmitters in the brain of its prey. When signals to and from nerve cells and muscles are disrupted, paralysis and respiratory failure sets in. The quantum of neurotoxin a king cobra can deliver in a single bite would be enough to kill 20 adult humans!

HUMP-NOSED PIT VIPER Hypnale hypnale

LOCATION: Cotigao WLS, Goa

Photo: Yuwaraj Gurjar.

The hump-nosed pit viper with its distinct upturned nose is eye-catching and dangerous. Its venomous bite belies its small, 0.3 m.- long frame and is fatal in some cases. Unlike the king cobra, it produces venom that is haemotoxic, very different in its design and working from neurotoxic venoms. Haemotoxins wreck the blood cells by disrupting clotting and damaging other tissues in its path. Nephrotoxic complications (kidney damage), are a common consequence of this snake’s bite. Little wonder then that hump-nosed pit vipers are considered to be as highly venomous as the Indian cobra, common krait and Russell’s viper.

BLACK-BANDED SEA KRAIT Laticauda semifasciata

LOCATION: Andaman and Nicobar Islands

Photo: Digant Desai.

Mercifully, sea kraits are shy, docile and not very aggressive, as they also happen to be one of the most venomous reptiles in the world. Their venom is, for instance, roughly 10 times more potent than that of a rattlesnake! To get a better idea of its toxicity, consider this… a sea krait can produce about 10-15 mg. of venom, but on account of its extremely high neurotoxin concentration, just a fraction of this amount is enough to kill. Put another way, because its venom potency is high, the quantum of venom it must deliver per bite is very low (just enough to incapacitate its prey).

BLUESPOTTED STINGRAY Neotrygon kuhlii

LOCATION: Andaman and Nicobar Islands

Photo: Digant Desai.

Bluespotted stingrays have those blue spots for a reason. The vivid colours are a warning sign to stay away. Their stingers are venomous and cardiotoxic. In simple words, the venom targets the heart muscles. If stung away from the chest, the venom is seldom fatal, but will cause excruciating pain because of the neurotoxin’s serotonin content. Its sharp sting also pierces the skin with a pressure that can cause severe tear, and the spine that encloses the sting is armed with serrated edges and, of course, the venom gland. Bluespotted stingrays are one of the most venomous of all the Myliobatiformes.

ASIAN COMMON TOAD Duttaphrynus melanostictus

LOCATION: Rajmachi, Maharashtra

Photo: Aasif Wadia.

The otherwise non-descript Asian common toad may seem harmless in appearance, but possesses special glands that secrete a poisonous substance capable of causing serious damage. It has characteristic black ridges that run between the eyes, nose and the paratoid glands, which produce a milky secretion that ‘advertises’ its poisonous nature by its pungent odour. When it feels threatened or stressed, it reacts by secreting the poison, which causes its potential victim’s nose and eyes to itch. When a snake or any other predator attempts to swallow the toad, the paratoid secretions causes broncho-constriction; resulting in a choking sensation that forces the predator to spit out the toad.

GIANT FOREST SCORPION Heterometrus sp.

LOCATION: Bandhavgarh, Madhya Pradesh

Photo: Dr. Anish Andheria.

This handsome black arachnid grows up to 10-20 cm. and has a powerful, venomous stinger. As the name suggests, it is one of the larger scorpion species. Its upturned tail carries the venom-inflicting stinger at its tip. Though it does not inject enough venom to kill an adult human, the neurotoxin in its venom causes agonising pain, inflammation, oedema, and redness that can last for days. A master hunter, it preys largely on insects and other small animals that it can overpower. Like a spider, it releases an enzyme-rich fluid that partially liquefies and digests the soft body parts of its prey, which will then be ingested, leaving behind a pile of keratinous debris.

A personal account by Gerry Martin, wildlife researcher and herpetologist

In Leporiang, Arunachal Pradesh, on a venom-collection expedition led by Rom Whitaker and me as part of the ‘Global Snakebite Initiative’, we chanced upon a stunning medo pit viper Trimeresurus medoensis. As I moved forward to catch the snake, I was momentarily distracted and things went awry. The viper struck with incredible speed and, before I could even shout, sank its 1/2 cm. long fang into the little finger of my left hand. Boy, did it hurt! The pain was acute, but we were more than a kilometre from our base camp. Taking meager consolation in the fact that pit viper bites are seldom fatal, we fashioned a sling out of my jacket and immobilised the bitten hand. Far from civilisation, my team kept a regular tab on my vital signs till we could get to a hospital. The damage caused by the viper’s venom was severe enough for me to require plastic surgery to restore my finger to its current form!

INDIAN GIANT TIGER CENTIPEDE Scolopendra hardwickei

LOCATION: Bandhavgarh, Madhya Pradesh

Photo: Nayan Khanolkar.

This giant centipede’s stunning colours add to its menacing appearance. It can grow up to 25 cm. and delivers a painful venomous bite that is able to paralyse the small vertebrates and invertebrates upon which it preys. This predatory ‘hundred-legged’ (in reality it does not have nearly as many) chilopod has modified front legs, known as maxillipeds, which deliver the venom into its hapless victim.

INDIAN ORNAMENTAL TARANTULA Poecilotheria regalis

LOCATION: Phansad Wildlife Sanctuary, Maharashtra

Photo: Vilas More.

One of the largest spiders found in the Indian subcontinent, this arachnid is one of the most venomous of all tarantulas. Adults have a leg span of between 17 and 20 cm. and are known to feed on small birds and animals that it is able to overpower. Venom is the weapon of choice for this old world, arboreal tarantula. Rural and tribal folklore have imparted the creature with a fearful reputation of causing several human fatalities. However, its venom, though potent, is not really strong enough to kill a human. But it can and will deliver an excruciatingly painful bite that can linger for days, causing swelling, redness and severe muscle spasms. To avoid direct confrontation, this beautiful spider flashes the transverse yellow bands under its first pair of legs in a distinctive defensive posture.

ARCTIINAE MOTH CATERPILLAR Family Erebidae

LOCATION: Bhimashankar Wildlife Sanctuary, Maharashtra

Photo: Ashish Nerlekar.

“Touch me not” is the message these caterpillars convey, and the warning should be taken seriously. Unlike bees, wasps and hornets, these striking little caterpillars differ in their manner of stinging. These caterpillars possess urticating spines or hairs all over their soft, vulnerable bodies. Each hair is a hollow tube that holds venom secreted from special glandular cells. When a potential predator makes contact, the spines break off and attach themselves to the offender’s skin, thus releasing the toxins that hurt, itch, cause a burning sensation, swellings, rashes and lesions. All this, almost instantly. That’s a stinging caterpillar for you.

PAPER WASP, Family Polistinae

LOCATION: Maharashtra Nature Park, Mumbai

Photo: Kane Kong Lew.

The wasp’s venom strategy is clever. It causes sharp pain, without inflicting permanent damage. That, it seems, is enough to scare away a potential predator. The paper wasp’s venom essentially fools its victim’s brain into believing that the extent of damage is great. The stinger injects the venom into the victim’s blood stream, which breaks down cell membranes. With the nerve cells under attack, the brain goes into high gear and triggers a flight syndrome, sparked by pain. That’s not all. To make the pain last longer, one of the venom ingredients, norepinephrine, slows blood flow. Because the envenomed blood remains in the body, the pain lingers until the blood finally flows out, taking the venom with it. Unlike honeybees, wasps can sting several times.

WEAVER ANTS Oecophylla smaragdina

LOCATION: Sanjay Gandhi National Park, Mumbai

Photo: Yuwaraj Gurjar.

This is one of only two extant species of weaver ants, the other, O. longinoda, is found only in tropical Africa. These ants do not ‘sting’, preferring to use their mandibles to inflict bites that cause skin irritation. In the process, a venom called formic acid causes the bite to be particularly painful. Interestingly, formic acid is used as an antidote to neutralise the stinging bite of fire ants and was probably the first natural product to be isolated by chemists from insects (ants) as far back as the 17th century.

FLAME LILY Gloriosa superba

LOCATION: Tadoba-Andhari Tiger Reserve, Maharashtra

Photo: Dr. Anish Andheria.

With beauty comes an element of danger! An apt name for this glorious, but poisonous, perennial creeper that contains toxic alkaloids, particularly colchicine, which can be fatal if ingested. The entire plant is toxic, especially the tubers, and can result in acute renal failure, cardiotoxicity, gastroenteritis and haematological abnormalities. These, of course, are only some of the clinical features that an unfortunate victim is likely to exhibit. Interestingly, the plant’s toxic constituents are used to counter snakebites and treat conditions ranging from arthritis to cholera. Colchicine, a chemical extracted from this plant, is being researched as a potential tool against cancers.

CRAB’S EYE Abrus precatorius

LOCATION: Tadoba-Andhari Tiger Reserve, Maharashtra

Photo: Dr. Anish Andheria.

Though the leaves of this plant are used in paan (betel leaves) for its cooling property, the abrin-containing seeds are highly toxic. A mere 0.1-1 g/kg. of abrin is lethal enough to kill. The seeds are attractive, small, shiny and beady red. Some may be orange and black in colour. Ingesting them intact may not harm, though when chewed and ingested, the abrin in the seeds will be absorbed through the gastrointestinal tract and can be deadly. The poison starts by affecting the gastrointestinal mucosal cells, eventually spreading to other organs as the protein synthesis within the cells is disrupted. Eventually, death in humans occurs on account of multiple organ system failure.

ON ANTIVENOM

Antivenin or antivenene is a biological product used in the treatment of venomous bites or stings. Antivenom is prepared by first milking venom from the desired snake, spider or insect. This venom is then diluted and injected into a horse, sheep, rabbit, or goat, whose immune systems produce antibodies, which are capable of neutralising the effect of the injected poison. The antibodies are shaped so as to bind to the chlorotoxin proteins of the venom. Once they attach themselves, they change shape and prevent the binding and blocking of channels in the victim. The human body is not capable of producing antibodies in such large quantities and as required after a venomous bite (though repeated exposure to venom in small doses may provide immunity in some cases).

No antivenom has yet been synthesised for venomous creatures such as sea snakes. Antivenom was effectively pioneered just about 100 years ago.

First appeared in: Sanctuary Asia, Vol. XXXV No. 4, April 2015.

 
 
 

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Anirudh Nair

April 8, 2015, 07:39 PM
 The organisms featured in the photo feature scream out 'Keep Your Distance'. I sure will when I encounter them in the wild!
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Gaurav T. Shirodkar

April 6, 2015, 11:54 PM
 Not just lovely images... each time we work on a feature, we learn so much from it. Thank you all for sharing these fantastic images with us.
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Kane Lew

April 6, 2015, 05:30 PM
 Excellent info and very nice article. Thank you very much.