# 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:** 8\ **Page:** 3
**Author:** ![Bippy\_the\_Beardless](https://avatars.discourse-cdn.com/v4/letter/b/ac8455/32.png) [@Bippy\_the\_Beardless](https://boards.straightdope.com/u/Bippy_the_Beardless)\ **Post date:** [July 5, 2005, 3:39pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/41 "2005-07-05T15:39:14Z")
For the plant kingdom, these two are quite small and very deadly [Destroying Angel and Death Cap](http://museum.gov.ns.ca/poison/angel.htm) ---
**Author:** ![Yeticus\_Rex](https://avatars.discourse-cdn.com/v4/letter/y/a698b9/32.png) [@Yeticus\_Rex](https://boards.straightdope.com/u/Yeticus_Rex)\ **Post date:** [July 5, 2005, 6:55pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/42 "2005-07-05T18:55:48Z")
Cecil did explain [“LD50”](http://www.straightdope.com/mailbag/mpoison.html) in a mailbag question about black widows and the Taipan snake, which should be considered as a contender in this thread. I think the definition of LD50 is the criteria that **Jon** is looking for. ---
**Author:** ![snailboy](https://avatars.discourse-cdn.com/v4/letter/s/97f17d/32.png) [@snailboy](https://boards.straightdope.com/u/snailboy)\ **Post date:** [July 5, 2005, 7:52pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/43 "2005-07-05T19:52:32Z")
> [@Bippy the Beardless](#): > > For the plant kingdom, these two are quite small and very deadly [Destroying Angel and Death Cap](http://museum.gov.ns.ca/poison/angel.htm) For the sake of correctness, both are members of the fungi kingdom, not the plant kingdom. ---
**Author:** ![Bippy\_the\_Beardless](https://avatars.discourse-cdn.com/v4/letter/b/ac8455/32.png) [@Bippy\_the\_Beardless](https://boards.straightdope.com/u/Bippy_the_Beardless)\ **Post date:** [July 5, 2005, 8:57pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/44 "2005-07-05T20:57:38Z")
> [@snailboy](#): > > For the sake of correctness, both are members of the fungi kingdom, not the plant kingdom. Perfectly correct, more info [here.](http://www.sidwell.edu/us/science/vlb5/Labs/Classification_Lab/Eukarya/Fungi/) ---
**Author:** ![Jon\_the\_Geek](https://avatars.discourse-cdn.com/v4/letter/j/bbce88/32.png) [@Jon\_the\_Geek](https://boards.straightdope.com/u/Jon_the_Geek)\ **Post date:** [July 5, 2005, 9:29pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/45 "2005-07-05T21:29:24Z")
> [@Yeticus Rex](#): > > Cecil did explain [“LD50”](http://www.straightdope.com/mailbag/mpoison.html) in a mailbag question about black widows and the Taipan snake, which should be considered as a contender in this thread. I think the definition of LD50 is the criteria that **Jon** is looking for. That gets me thinking in the right terms, at least. I’m thinking this, others might point out flaws that make me change it: Volume category: (venom injected/LD50)/volume Mass category: (venom injected/LD50)/mass I _think_ that would give us something equivalent to “deadliness per size,” but correct me if I’m wrong. Of course, if venom injected is less than LD50, I don’t think it can count as deadly by my very rough definition. Does anyone see a flaw in my formula? ---
**Author:** ![cher3](https://avatars.discourse-cdn.com/v4/letter/c/da6949/32.png) [@cher3](https://boards.straightdope.com/u/cher3)\ **Post date:** [July 5, 2005, 9:49pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/46 "2005-07-05T21:49:01Z")
Should things that you have to eat (frogs, mushrooms) be allowed to win this contest over things that you might just run into accidentally (spiders, jellyfish)? ---
**Author:** ![Jon\_the\_Geek](https://avatars.discourse-cdn.com/v4/letter/j/bbce88/32.png) [@Jon\_the\_Geek](https://boards.straightdope.com/u/Jon_the_Geek)\ **Post date:** [July 5, 2005, 11:37pm UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/47 "2005-07-05T23:37:45Z")
> [@cher3](#): > > Should things that you have to eat (frogs, mushrooms) be allowed to win this contest over things that you might just run into accidentally (spiders, jellyfish)? I think they should go in separate categories, but I’d like to see both 🙂 ---
**Author:** ![enigmatic](https://avatars.discourse-cdn.com/v4/letter/e/898d66/32.png) [@enigmatic](https://boards.straightdope.com/u/enigmatic)\ **Post date:** [July 6, 2005, 8:38am UTC](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895/48 "2005-07-06T08:38:51Z")
LD-50 is probably the best way of doing this but is still not exactly without problems. Human LD50 data is understandably very patchy, it is often drawn from a handful of cases of unfortunates and the dosage information is usually a very crude guesstimate, it also tends to represent those individuals unfortunate enough to be more susceptible to poisoning such as children. better information is often available for animals but depending on the metabolic differences involved you can’t just scale up the masses to get a workable figure for humans (humans can be tens or even hundreds of times more or less susceptible to some poisons than a paticular animal, in fact you can get still get huge variation between individual humans). Once you have your LD50 (for the correct route of absorbtion) you still have to find out how much venom is absorbed in a typical envenomation. If I was to guess I’d of thought it would come down to the frogs or the coneshells, does anyone know how small puffer fish can get?. I should imagine if you were looking for the absolute champion in the lethality/mass stakes though Clostridium Botulinum has it by a LONG way [Previous page](https://boards.straightdope.com/t/smallest-living-thing-that-can-kill-a-human/310895.md?page=2)