# Smallest living thing that can kill a human? **URL:** \ **Category:** Factual Questions\ **Created:** [July 3, 2005, 3:40am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895 "2005-07-03T03:40:43Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Cunctator](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Cunctator](https://boards.straightdope.com/u/Cunctator)\ **Post date:** [July 3, 2005, 11:19pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/21 "2005-07-03T23:19:50Z")
> [@Arwin](#): > > How about a blue ring octopus? Another delightful creature mentioned on the list of [Australia’s top 10 dangerous animals.](http://www.australianfauna.com/t10dangerous.php) ---
**Author:** ![chrisk](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@chrisk](https://boards.straightdope.com/u/chrisk)\ **Post date:** [July 3, 2005, 11:46pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/22 "2005-07-03T23:46:16Z")
> [@scr4](#): > > I don’t think so. An HIV virus\* is about 60nm in radius, so assuming a density of 1, its mass is 5x10[sup]-19[/sup] kg. Annihilation of this much antimatter releases 0.1 Joules of energy. That’s 0.02 calories, i.e. enough to raise the temperature of 1/4 teaspoon of water by 0.02 degrees. (Unless I did something wrong.) > > \*Yes, I know that’s redundant. What am I supposed to say, “an HI Virus”? Hmmm… that’s very interesting!! What about an antimatter bacterium?? ---
**Author:** ![kjckjc](https://avatars.discourse-cdn.com/v4/letter/k/e36b37/32.png) [@kjckjc](https://boards.straightdope.com/u/kjckjc)\ **Post date:** [July 4, 2005, 12:43am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/23 "2005-07-04T00:43:07Z")
I think that candirú are really small and if one swam up my urethra I would have to kill myself. Lots. But I would think the winner would be a gravitational singularity. Maybe the “Big Bang Singularity” itself. Getting one of them in you can ruin your whole day. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [July 4, 2005, 1:04am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/24 "2005-07-04T01:04:37Z")
> [@kjckjc](#): > > But I would think the winner would be a gravitational singularity. As far as I know, gravitational singularities aren’t living things. As for antimatter, I’m going to assume that equivalent of 1-gram TNT can kill a person. That’s 4,000 Joules. Amount of antimatter needed to generate that energy is about 22 picograms. Assuming a density of 1 gram/cm[sup]3[/sup], that’s a cube 2.7 microns on each side. That’s comparable to some types of bacteria. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [July 4, 2005, 1:19am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/25 "2005-07-04T01:19:53Z")
> [@Jon the Geek](#): > > I’m thinking along the lines of something that can bite or sting me once on, say, the hand, and the venom (or whatever, as long as it isn’t alive) it injects, without reproducing, would kill me if I didn’t receive some sort of anti-venom. Well that clears it up a bit. Now for the next clarification, how certain does the death have to be? Realistically a healthy young person has a better chance of being kicked to death by a duck than dying of a redback bite, so do they still count? Similarly with irukandji healthy people would never die from being stung on the hand no matter how severe it is. A severe sting to the head or torso nay be fatal but AFAIK everyone who has ever actually died had a pre-existing heart condition that was aggravated by the sting. So unless you suffer from cardiomyopathy do we have to discount the irukandji. If you want something small that has better than a 1 in a hundred chance of killing a healthy person with one ‘bite’ to the hand you really are restricting yourself to the snakes. > [@Jon the Geek](#): > > I’m not sure whether red-back spiders beat out black widows… They are the same animal as far as anyone can tell. Just different names for slightly different regional variation in same species. Black Widow in the US, Redback in Australia , Kaitipo in New Zealand and a dozen oither names in other parts of its range. A few taxonomists list them as different species or hybrids but AFAIK majority opinion at the moment is they are all the one animal. > [@Shalmanese](#): > > What about ticks? I hear about 2 people in Australia die every year due to tick bites. One problem. The OP wants something that can bite him once and kill him. Paralysis ticks need to feed for several hours at least to deliver a fatal dose of venom. They don’t count. Two, two problems. The only paralysis ticks fatal to humans are the adult females, and they’re in the same size range as redbacks, and much heavier. Three. Three problems. Amongst our problems are such diverse elements as time of exposure required, comparative size and the fact that I doubt any healthy adults die form ticks. Children and animals sure, but it’s hard to imagine a normal person dying. Given that it’s rare for animals to die these days I doubt of two adults a year are killed. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [July 4, 2005, 1:26am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/26 "2005-07-04T01:26:26Z")
> [@enipla](#): > > I beleive a Black Widow can kill the young and elderly. They are quite small. Due to osteoporosis, no doubt. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [July 4, 2005, 1:33am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/27 "2005-07-04T01:33:39Z")
> [@Fear Itself](#): > > Due to osteoporosis, no doubt. Stop being silly. Young people are small because they haven’t had enough time to grow. Osteoporosis. Pshaw. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [July 4, 2005, 4:24am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/28 "2005-07-04T04:24:50Z")
> [@scr4](#): > > \*Yes, I know that’s redundant. What am I supposed to say, “an HI Virus”? If you are referring to a single organism, it would be an “HIV virus particle”. (I’ve seen the term “viron” used as well, but not in technical literature.) “HIV” refers to the configuration or colloquial taxinomy, and “virus particle” or “particle” indicates that you are referring to a singular instance of it. That said, (without pulling out any references) your calcs look good to me. It is surprising how _little_ damage small quantities of antimatter can really do, which is a good thing since cosmic rays frequently [create antiparticles](http://livefromcern.web.cern.ch/livefromcern/antimatter/everyday/AM-everyday02.html) in the atmosphere all the time. (And my sixth-grade science teacher berated me in front of the class for suggesting that antimatter exists. Public education. :rolleyes: ) Stranger ---
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [July 4, 2005, 6:40am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/29 "2005-07-04T06:40:59Z")
Although it’s probably not what the OP contemplated, one must ponder the power of a thought. Surely they are alive, and must be quite tiny-can a neurosurgeon place a scale next to a synapse and determine the size of a concept? Are thoughts lethal? Surely a suicidal mindset satisfies that query, and we might add the sociopath and other predatory frames of mind who effectively kill others via their behavior. ---
**Author:** ![Arwin](https://avatars.discourse-cdn.com/v4/letter/a/51bf81/32.png) [@Arwin](https://boards.straightdope.com/u/Arwin)\ **Post date:** [July 4, 2005, 8:14am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/30 "2005-07-04T08:14:05Z")
> [@Blake](#): > > Well that clears it up a bit. > > Now for the next clarification, how certain does the death have to be? > > Realistically a healthy young person has a better chance of being kicked to death by a duck than dying of a redback bite, so do they still count? > > Similarly with irukandji healthy people would never die from being stung on the hand no matter how severe it is. A severe sting to the head or torso nay be fatal but AFAIK everyone who has ever actually died had a pre-existing heart condition that was aggravated by the sting. So unless you suffer from cardiomyopathy do we have to discount the irukandji. > > If you want something small that has better than a 1 in a hundred chance of killing a healthy person with one ‘bite’ to the hand you really are restricting yourself to the snakes. Not so for my suggestion though, the blue ring octopus. Certain death for just about everyone, within as little as 3 minutes. And with a maximum of 20cm, it beats the best snake both in terms of certainty and speed of death, and size. > [@](#): > > They are the same animal as far as anyone can tell. Just different names for slightly different regional variation in same species. Black Widow in the US, Redback in Australia , Kaitipo in New Zealand and a dozen oither names in other parts of its range. Yes, they are considered to be closely related. But I did get the impression that the redback was somewhat smaller/more poisonous. The poison of a black widow has been highly overrated, but generally what makes an animal feature highly on a ‘most dangerous’ list is not how likely you are to die, but how many people it kills every year. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [July 4, 2005, 9:55am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/31 "2005-07-04T09:55:33Z")
> [@Arwin](#): > > Not so for my suggestion though, the blue ring octopus. Certain death for just about everyone, within as little as 3 minutes. And with a maximum of 20cm, it beats the best snake both in terms of certainty and speed of death, and size. There are any number of 20cm snakes that would kill a human without much room for chance. The other problem is that AFAIK there’s still a big question mark about the source of the venom. Nobody has ever isolated an actual venom production cell/gland from the animal. Last I heard it was even bets that the octopus was either stealing the venom form its prey and storing it or else using gut basteria to do the same trick. If it’s simply utilising bacterial toxins I’m not sure it would count. > [@](#): > > Yes, they are considered to be closely related. But I did get the impression that the redback was somewhat smaller/more poisonous. That would depend on the individual I imagine. Big spiders come fofrm little spiders so either species comes in a variety of sizes even if the maximum adult size for one strain is somewhat larger. > [@](#): > > The poison of a black widow has been highly overrated But not half as much as the redback. Given that AFAIK no adult has ever died from a redback bite that’s some pretty serious publicity for a pretty innocuous bug. ---
**Author:** ![Arwin](https://avatars.discourse-cdn.com/v4/letter/a/51bf81/32.png) [@Arwin](https://boards.straightdope.com/u/Arwin)\ **Post date:** [July 4, 2005, 10:37am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/32 "2005-07-04T10:37:12Z")
> [@Blake](#): > > There are any number of 20cm snakes that would kill a human without much room for chance. Such as? > [@](#): > > The other problem is that AFAIK there’s still a big question mark about the source of the venom. Nobody has ever isolated an actual venom production cell/gland from the animal. Not true. The animal has two glands equal the size of its brain. The one produces poison it uses on its prey, the other for defense against predators. It is transmitted through saliva and the octopus can penetrate a wetsuit to deliver a lethal blow. [http://www.barrierreefaustralia.com/the-great-barrier-reef/blueringedoctopus.htm](http://www.barrierreefaustralia.com/the-great-barrier-reef/blueringedoctopus.htm) But actually, I see that something can be done to survive its bite - artificial respiration. Apparently, keeping the lungs going artificially (and sometimes heart) until the poison’s worn off, has a fair chance of saving you, without too many bad side-effects. That must be one scary thing to go through though, if you make it! > [@](#): > > Last I heard it was even bets that the octopus was either stealing the venom form its prey and storing it or else using gut basteria to do the same trick. If it’s simply utilising bacterial toxins I’m not sure it would count. Nah, that’s not it. See above. > [@](#): > > But not half as much as the redback. Given that AFAIK no adult has ever died from a redback bite that’s some pretty serious publicity for a pretty innocuous bug. Depends on where you live. In the Netherlands, everyone knows the Black Widow, but nobody knows the Redback, really. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [July 4, 2005, 10:55am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/33 "2005-07-04T10:55:44Z")
I suppose if a gnat happened to have a speck of plutonium lodged on its back and you inhaled it… ---
**Author:** ![Fromage\_A\_Trois](https://avatars.discourse-cdn.com/v4/letter/f/a88e57/32.png) [@Fromage\_A\_Trois](https://boards.straightdope.com/u/Fromage_A_Trois)\ **Post date:** [July 4, 2005, 12:11pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/34 "2005-07-04T12:11:39Z")
> [@Bryan Ekers](#): > > I suppose if a gnat happened to have a speck of plutonium lodged on its back and you inhaled it… Well, then you’d gain superhero powers and become GnatMan! ---
**Author:** ![enigmatic](https://avatars.discourse-cdn.com/v4/letter/e/898d66/32.png) [@enigmatic](https://boards.straightdope.com/u/enigmatic)\ **Post date:** [July 4, 2005, 1:28pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/35 "2005-07-04T13:28:53Z")
I think there are a couple of problems here 1. - There is an awful lot of bullshit propogated about small poisonous creatures and their deadliness. 2. - Many of these animals while theroetically capable of killing, a healthy adult is unlikely to be die as a result of their bite, many poisonous bugs and most (if not all) poisonous spiders fall into this category. Also some of the previously described animals tend to cause fatalities when people sustain a lot of stings from a swarm of creatures (like the jellyfish) Does the animal actually have to actively poison someone to win this or could the person die as a result of ingesting the creature? Should the likelyhood of succesful medical treatment influence the judges final decision? ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [July 4, 2005, 1:38pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/36 "2005-07-04T13:38:28Z")
> [@enigmatic](#): > > Does the animal actually have to actively poison someone to win this or could the person die as a result of ingesting the creature? If we go with ingesting the creature the poison dart frog has to be the winner hands down. They are considered among the most poisonous and perhaps THE most poisonous creatures on the planet and the littlest of them are pretty darn small. It does not take much of their poison to kill an adult human and the poison looks to be invariably fatal. I do not know if you could be saved even if you ate the frog in a hospital emergency room. ---
**Author:** ![enigmatic](https://avatars.discourse-cdn.com/v4/letter/e/898d66/32.png) [@enigmatic](https://boards.straightdope.com/u/enigmatic)\ **Post date:** [July 4, 2005, 6:03pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/37 "2005-07-04T18:03:12Z")
The poison arrow frogs are thought to absorb their toxins from the bugs that they eat, and so can be disqualified on the same grounds as the blue ringed octopus (one of the toxins they release is in fact tetrodotoxin). Their is enough venom in some species of the frogs to kill a human consistantly (although I think you are exaggerating their deadliness slightly) ---
**Author:** ![SlyFrog](https://avatars.discourse-cdn.com/v4/letter/s/a3d4f5/32.png) [@SlyFrog](https://boards.straightdope.com/u/SlyFrog)\ **Post date:** [July 4, 2005, 6:48pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/38 "2005-07-04T18:48:59Z")
First, I’m not sure the frog should be ruled out because it gets its poison from something it eats. The poison is still part of the frog, regardless of the original source. It’s not really something independently alive that kills you; it is toxin generated by the frog metabolizing its food, no? Second, and I think by far the most important question raised by this thread: Why in the hell does anyone live in Australia? If you want the experience, it seems more intelligent to simply stay in your home country and play Russian Roulette once per year. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [July 5, 2005, 2:53am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/39 "2005-07-05T02:53:08Z")
> [@Arwin](#): > > > [@](#): > > > > There are any number of 20cm snakes that would kill a human without much room for chance. > > Such as? Perhaps a better question would be which ones _wouldn’t_. I honestly can not think of one snake that is usually deadly to adult humans that wouldn’t be deadly by the time it reached 20cm. Can you actually name any snakes that are only deadly _after_ they reach 21cm? > [@](#): > > Not true. The animal has two glands equal the size of its brain. The one produces poison it uses on its prey, the other for defense against predators. It is transmitted through saliva and the octopus can penetrate a wetsuit to deliver a lethal blow. > > [http://www.barrierreefaustralia.com/the-great-barrier-reef/blueringedoctopus.htm](http://www.barrierreefaustralia.com/the-great-barrier-reef/blueringedoctopus.htm) Hang on. That reference says no such thing. It says that the poison is _contained_ in salivary glands. That page doesn’t even use the word ‘produce’. You are misquoting horrendously. In contrast, without misquoting I can provide: “Blue-ringed octopus are thought to harness bacteria in their salivary glands to produce tetrodotoxin found in poisonous puffer fishes.” [http://www.australiancephalopods.com/occy\_blue\_ring.html](http://www.australiancephalopods.com/occy_blue_ring.html) “It was a mystery why such a diversity of unrelated organisms would all evolve the same toxin, until it was recently discovered that bacteria associated with many of these animals actually produce TTX. This is the case in blue-ringed octopuses. Their salivary glands harbor dense colonies of TTX-producing bacteria.” [http://www.nhm.ac.uk/hosted\_sites/tcp/bluering2.html](http://www.nhm.ac.uk/hosted_sites/tcp/bluering2.html) The blue-ringed octopus found in Australian waters accumulates tetrodotoxin in a special salivary gland and infuses its prey with toxin by bite. This octopus contains tetrodotoxin-producing bacteria. [http://www.chm.bris.ac.uk/motm/ttx/ttxc.htm](http://www.chm.bris.ac.uk/motm/ttx/ttxc.htm) There’s no secret that the poison is stored/contained in the salivary glands. But it is not produced by them. You misread that page completely. Although my search has turned up one thing. Apparently it’s now accepted that they are extracting the toxin directly form symbiotic bacteria. Presumably the prey harvesting theory has been ditched. > [@](#): > > Nah, that’s not it. See above. I did see above, You misread the reference and then misquoted it. The reference doesn’t even contain the word ‘produced’ much less discuss toxin production. That word was something you added. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [July 5, 2005, 2:53am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/40 "2005-07-05T02:53:20Z")
> [@enigmatic](#): > > Their is enough venom in some species of the frogs to kill a human consistantly (although I think you are exaggerating their deadliness slightly) There are something like over 100 species of poison dart frogs and they vary in their lethalness. That said the most lethal of them are considered to be the MOST poisonous of creatures on the planet. The toxin they get via their food sources is absolutely lethal. You may well survive a Red Back spider bite. You almost certainly would not survive ingesting poison dart frog toxins. > [@](#): > > The bright coloration of the poison dart frog serves as a warning to potential predators that it is one of the most poisonous animals on earth. > > SOURCE: [http://www.amnh.org/exhibitions/expeditions/treasure\_fossil/Treasures/Poison\_Dart\_Frogs/frogs.html?aa](http://www.amnh.org/exhibitions/expeditions/treasure_fossil/Treasures/Poison_Dart_Frogs/frogs.html?aa) If you Google “poison dart frogs” you will find the above sentiment repeated consistently. [Previous page](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895.md?page=1) [Next page](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895.md?page=3)