What's the biggest thing you think you can take in a fight? According to a YouGov poll, 6% of Americans reckoned they could beat a grizzly bear bare-handed. But lest you take this as evidence of a, let's say, optimistic national spirit, only 72% thought they could take a rat. I think I could win that fight.

What's the smallest thing that could take you? While I like to think that, if cornered, I could take all manner of small rodent, I’m not sure even the brave 6% would take a 10-gram bullet to the brain. They also probably couldn’t win against 300 mg of cyanide, 10 mg of sarin gas, or just 0.1 μg of botulinum toxin, the deadliest known toxin. Numbers this small can be hard to grasp. All three substances are deadly, but the lethal dose of cyanide is more than a million times greater than that of botulinum toxin. A grizzly bear, by contrast, is merely a thousand times heavier than a rat.

We are still not close to the most dangerous object of all, pound for pound. A single smallpox virion weighs less than 10⁻¹⁴ grams, less than a millionth the mass [...]

---

Outline:

(03:29) Smaller, cheaper, scarier

(06:49) The rest of the arsenal

(08:39) What can we do?

(10:22) Appendix: Lethality estimates

The original text contained 2 footnotes which were omitted from this narration.

---

First published:
August 3rd, 2026

Source:
https://www.lesswrong.com/posts/WusL5mDbtJBjdTxCh/why-biological-weapons-are-scary-and-what-we-can-do-about-it

---

Narrated by TYPE III AUDIO.

“Why biological weapons are scary, and what we can do about it” by djbinder

LessWrong (30+ Karma)

“Why biological weapons are scary, and what we can do about it” by djbinder