Top 5 Poisonous Animals in the World


“Poison is in everything, and no thing is without poison. The dosage makes it either a poison or a remedy. “-Paracelsus, Father of Toxicology

There are lots of things in the animal world that you want to avoid but there are certain things that you should always stay away from no matter what. Their venoms are deadly and vigorous that acts within seconds and starts taking its toll in next few minutes and eventually death occurs if not treated. Are you a 6’4 well-built human machine or a chair-loving bibliophile? Truthfully it doesn’t matter. You are human and you have a closed circulatory system.  

In biology, a poison is a substance secreted by a gland in organisms that is harmful to a foreign body when absorbed in sufficient amount through the epithelial tissue such as the skin or gut. Venom however needs a mode of administration like a fang or a claw. After the venom or poison is in the circulatory system of a foreign body it now becomes a toxin that antigens try to act against but usually fail to do so without antivenom. 

We shall uncover how nature has gifted these beautiful creatures for survival. I’ve chosen five members of the animal kingdom that can either deliver vicious venom or hold poison in their body that is scientifically enough to kill human beings. As the thinking man let’s avoid them. I present to you the top 5 animals with killer poison and venom:

1.The Poison Dart Frog


In the humid forests of South America you might meet a brightly colored frog, the poison dart frog. The bright colors means,” if you hurt me it’ll cost you.” In ethology called aposematic coloration. They are only a mouthful and while frogs are the easiest targets that predators usually prey upon don’t be fooled, there is only one species of snake that has been able to develop immunity to the alkaloid poison that oozes from its skin. The level of toxicity of the poison is really astounding that it has a chemical called epibatidine[6353], a painkiller 200 times as potent as morphine which has shown extreme gastrointestinal side effects.


Fortunately for those of us who love to roam the wet woods poison dart frog species are classified as endangered or critically endangered under IUCN red list status (mainly due to habitat loss and not predation) and they don’t live all around the globe. Even if they were that is to say if people breed them away from wild they tend to significantly lose their toxin levels arguably because of its change in diet.



Of course it has no mode of injecting them directly into a blood stream but who’s so say we won’t pick it up thinking mistakenly. The poison of golden-colored has enough toxins on average that can kill 10-20 men and around 10000 mice. So yes, don’t pick one of these little guys up. 

Poison Dart Frog(124518)
Credit: Adrian Pingstone in September 2005 and released to the public domain
Poison Dart Frog(124519)
Credit: Photographed by Adrian Pingstone in May 2005 and released to the public domain.

2. The Box Jellyfish


The sea wasp as it is infamously known. Behold one of nature’s impeccable tactical designs: the box jellyfish. They are hunters so to protect those delicate tentacles they must kill quickly. The nematocysts on its tentacle will envenomate its prey or anything it sees as threat. The excruciating venom causes leakage of potassium leading to hyperkalemia; which then causes cardiac arrest within 2-5 minutes (Angel Yanagihara of University of Hawaii).[6358]

 The venom is undoubtedly one of the most dangerous in the world but that’s not even the scary part; these marine stingers are almost invisible in the waters and you most likely won’t notice it closing distance on you. Another hurdle is that after being stung reaching off shore is an extremely difficult task. You have to get aid (vinegar, antivenom) [6359]pretty fast and remove the tentacles without getting it on other parts of the body.

 So yes prevention is better than cure so always have a thin layer of nylon over you when entering the waters of Indo-Pacific.

Box Jellyfish(124520)
Credit: Guido Gautsch, Melbourne, Australia

3. The Brazilian Wandering Spider


Guinness World Records has the Brazilian Wandering Spider as the “most venomous spider” since 2010[6365]. Often called the banana spider known for hiding in fruit boxes, they are aggressive and confidently go in attack mode if threatened. They have a battle stance, it raises its frontal legs up with the entire body and the hind legs cocked with the earth ready to attack any moment.

 [6364]The venom is one of the deadliest ever known to science, unquestionably so from an arachnid. It causes loss of muscle control and breathing which leads to paralysis and asphyxiation. Another danger for human male victims is that it causes a condition called priapism where long hours (even days) of uncomfortable and painful erection occur resulting in impotency.  If it makes a full intravenous sting it only needs 6 μg to kill a 20 g mouse that is 6/1000000 grams and not more to kill a human.

 The spider’s wandering nature is what makes it really dangerous to us. Unlike other spiders they don’t weave a web. They actively hunt during the night and at the crack of dawn crawl into fruit crates, fallen leaves, shoes, clothes etc.  You don’t want to take your eyes off this spider if you encounter one and yes don’t forget to check your shoes next time.


Brazilian Wandering Spider(124523)
Credit: João Burini, Brazil

4. The Inland Taipan


This snake can grow up to 2.5 meters in length. The Inland Taipan can inject venom of 44 mg and can go as high as 110 mg, enough to kill 100 grown men and over 100000 mice. The venom is highly neurotoxic and one component of it is Taipoxin [6367] [6368]a chemical that stops neurotransmitters such as acetylcholine from being released from our motor nerve cells which results in paralysis of respiratory muscles causing asphyxia. This neurotoxin is the most lethal ever isolated from a snake. The median lethal dose is only 2 micrograms per kg (parts per billion) for mice.

This snake is not aggressive and won’t go attacking humans unless pushed beyond limit but our smaller mammal friends (rodents, mice) are not as lucky as us. Suggestively because of its shy and reclusive nature it will return for its kill after the prey has completely succumbed to the venom.

 If Central Australia is a preferable vacation spot then tap the ground hard when walking, it is afraid of you as much as you are of it.


The Inland Taipan
Credit: XLerate (wikipedia)

5. The Blue-ringed Octopus

Waters extending all the way from the borders of India to Australia, the Indo-Pacific waters, has a dangerous creature thriving in it. It is known as the blue-ringed octopus for it changes its regular brown rings to bright blue when agitated.


Two types of glands produce venom separately: the first kind to paralyze its prey and the second one (much stronger and faster-acting) in act of self-defense. The venom, produced by the salivary gland, has a neurotoxin called tetrodotoxin[6370][6372] which ceases motor functions due to blockage of sodium channels. In not long respiratory arrest, cardiac failure and paralysis follow.


[6373]There is no antidote of tetrodotoxin to date even though bites in humans are not that common due to its docile nature and prescient hiding techniques. Treatment includes immediate first-aid and CPR for up to 24 hours in a hospital.


Blue-ringed octopus(124531)
Credit: Jens Petersen(1829–1900)