7 November 2012

World's most poisonous animals

The world is a cruel and unforgiving place; particularly for wild animals who spend their lives roaming the Great Outdoors. Only the best and fittest individuals are able to survive in it, which largely involves evading capture or the hunting and killing of smaller and weaker animals. Simply put, an animal must either kill or be killed if it is to carry on living. As melodramatic as this sounds, it's one of the most fundamental rules of Nature.

Due to this, animals have come up with a whole range of ingenious weapons to fight with and defences that guard against their demise. From horns to armour plating, animal evolution has been driven the effectiveness of their arsenals and no weapons are more deadly and feared that poisons - toxic chemicals that are injected via bites, stings or touch to incapacitate or kill both predators and prey alike.

Although there are thousands of different poisonous animals, there is a huge range in their toxicity and the damage that they can cause, meaning that not all poisonous animals are deadly. However, there are many that are incredibly dangerous and this post provides a comprehensive list of the most poisonous animals in the world.

10: Pufferfish

Pufferfish mainly use their poison in self defence. When they are threatened by a predator, pufferfish swallow large quantities of water and inflate their body so that their toxic spines stand on end.

Pufferfish poison produces a rapid and violent death within 24 hours of being stung, where an individual experiences heart palpitations, difficulty in breathing, muscle spasms/paralysis and vomiting. There is no known cure to their poison and victims eventually find themselves unable to breath, and die.

9: Golden dart frog

The venom of the golden dart (or poison) frog, Phyllobates terribilis, was once rubbed onto darts and arrowheads by hunters in South America to make their weapons even more deadly.

The golden dart frog is the most poisonous amphibian on Earth and excretes its toxins directly onto its skin. Due to this, it is extremely dangerous to pick up one of the frogs, and there is enough venom spread over the surface of its body to kill 20, 000 mice or 10 adult humans.

8: King cobra

The snake-eating king cobra, Ophiophagus hannah, is the world's longest venomous snake and can grow to lengths of 5.6 metres (18.5 feet).

As well as possessing a very potent poison that can kill in itself, the king cobra is the master of 'overkill' and injects huge quantities of venom with each bite. For example, it injects 5 times more poison into its victims than does the infamously violent black mamba. In fact the king cobra injects enough venom to kill an elephant within 3 hours, if it bites them in a vulnerable area such as on their trunk.

7: Brazilian wandering spider

The Brazilian wandering spider, Phoneutria nigriventer, is also called the armed spider and is extremely aggressive, living in banana plantations throughout Brazil.

The Brazilian wandering spider is the most deadly arachnid in the world and is named due its tendency to wander into peoples homes and clothing, where they hide during the day. Their bite is not only deadly and extremely painful, but can also lead to sustained and highly uncomfortable erections in men (priapisms) that often leads to long-term impotence.

6: Stonefish

Stonefish are found in the shallow waters of Eastern Australia and actually use their poison for self defence, raising their spines only when threatened rather than to hunt their prey of shrimps and small fish.

The toxins that the stonefish inject through their spines are said to be so painful that many who have been stung have said that they would rather have had their limb amputated than have endured the pain. In fact, the pain that they cause is believed to be on the threshold of human sensation, being described by many female victims as being infinitely worse than childbirth. Once stung, an adult will normally die within two hours if they do not seek immediate medical help.

5: Deathstalker scorpion

The Deathstalker scorpion, Leiurus quinquestriatus, probably has one of the most unpleasant poisons on this list. After being stung, a person will suffer from unbearable pain before falling into a deep coma. While in this coma, the scorpion's toxins destroy the person's nervous system, leading to irreversible paralysis and eventually, death.

Despite having one of the most potent venoms in nature, the Deathstalker scorpion will probably save more lives in the future than it ends. Their poison contains a unique clorotoxin that can be modified by scientists so that it attaches only to cancerous cells in the human brain, leaving healthy cells alone. Chemotherapeutic drugs can be attached the chlorotoxin before it is injected, effectively forming a 'magic bullet' drug that hunts down and destroys the cells in brain tumours.

4: Blue-ringed octopus

The blue-ringed octopus, Hapalochlaena lunulata, is tiny, being scarcely larger than a  golf ball and typically feeds off small crabs and shrimps.

Like all species of octopus, the blue-ringed octopus possess specialised skin cells that allow them to change colour depending on their mood. Oddly, their lethal and incurable bite is painless and usually contains enough venom to kill 26 adult humans.

3: Marbled cone snail

The marbled cone snail, Conus marmoreus, is a predatory snail that lives in the Indo-Pacific Ocean. Relative to its size, the snail is the most poisonous animal on the planet.

Due to the slow and cumbersome nature of snails, some of you no doubt find the whole idea of a predatory snail as being unlikely. It would seem that you are not alone in this and the snails appear to have noticed their limitations in speed and manoeuvrability as well, actually hunting via a poisonous 'harpoon' that they launch at fish that get too close. This harpoon is absolutely lethal, being loaded with enough poison to kill 20 adult humans.

2: Inland taipan

Also called the small-scaled snake and the fierce snake, the inland taipan, Oxyuranus microlepidotus, is native to Australia and is the most venomous snake in the world; with its poison being able to kill an adult human within 45 minutes after being bitten.

An adult inland taipan is thought to have enough venom in its body at any one time to kill 250, 000 mice or 100 humans! Unbelievably, its nervous system attacking venom has been calculated to be 50 times more deadly than the common cobra and 10 times as toxic as the Mojave rattlesnake.

Fortunately for us, the inland taipan is an exceedingly shy snake that rarely bites unless it has been provoked;  and even then, bites are rare. Due to this docile nature, no human deaths* have ever been recorded.

1: Box jellyfish

There are several different species of box jellyfish spread throughout many tropical and subtropical oceans, which all contain extremely damaging toxins, and can be easily distinguished by their cube-shaped 'heads'.

Sadly, box jellyfish have been responsible for more than 5, 500 recorded deaths since 1954*. Their poison is highly potent and attacks their victim's heart, skin and nervous tissue. If stung by a box jellyfish, a person has little chance of survival unless they receive medical help almost immediately. Fortunately, the acetic acid found in vinegar can counteract some of the effects of the poison and stop any undischarged nematocysts from injecting more venom into the wound caused by their tentacles.

Despite its incredibly potent venom and the vast number of deaths box jellyfish have caused, it is worth noting that some scientists argue that they not actually the most poisonous animal in the world and that the highly esteemed honour should be awarded to its closely related cousin, the tiny Irukandji jellyfish.

* to the best of my knowledge, the figure was correct at the time this article was published.

1 comment:

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