I know ANOTHER weird cockroach question, but bare with me.

I have this very W.I.P story about an non-governmental organization that wants to send out people to make peaceful first contact(not technically first contact but they do not know that) with sapient cockroaches, German cockroaches to be exact.

enter image description here

Anyway, they need to shrink them down to around 1 inch(1/72 of their normal size) in order for them to properly interact and be respectful.

To make a long story short, they, spoilers, turn out not to be so friendly, and end up slaughtering like 21 of the 28 people they sent out, heck, one literally slapped the head off the dude that went for a handshake.

It makes for a cool/creepy scene, but I was wondering if the massacre would mostly likely turn out that way 'realistically', and if I should maybe leave or even have more survivors.

Here is some context:

  1. The humans and whatever else is shrunk down retain their equivalent stats(strength, speed, durability) when shrunk. Square-Cube Law does not negatively or positively affect them. They are 50/50 adult men and women.
  2. The humans have no weapons. The roaches do, but in this case this one is unarmed.
  3. They have shrunken vehicles(a car, cargo van, and a motorcycle) and are relatively near them.
  4. Most of the roaches are pretty much physically the same as a German cockroach except they are a bit taller maybe, around an inch and they have 'hands' now. They pretty much keep their stats from current living German Cockroaches(some can fly, but not this one).

This is not a plot question, I am just trying to get the main antagonist species worked out, the actual outcome of this incident will be worked out by me. Also, as stated in the first bit of context, the bad/good effects of Square-Cube Law is not in play, please do not bring it up.

  • $\begingroup$ As I get it, the cockroach can only bite as a means to do harm to something. So, if humans scatter, a single cockroach won't do. There might be an ambush or so, swarming is the usual strategy for insects when they fight, but alone - no way. $\endgroup$
    – Vesper
    Apr 17, 2023 at 13:23
  • 2
    $\begingroup$ Just off the cuff, I'm thinking "barehanded" fighting wouldn't work well at that scale. Material strength doesn't change as much as the mass does? Combat at that scale in the insect world is almost entirely about biting and piercing. A bug slapping another bug would not, I think, cause much impact. They just don't have the mass relative to the material strength of their bodies. (Notable exception: the mantis shrimp punch, but that's a specialized behavior for their environment.) $\endgroup$
    – JamieB
    Apr 17, 2023 at 14:11
  • $\begingroup$ I get what you are saying, but in this case, the method that shrunk the humans somehow also scaled down material strength. So in this case, the humans have equivalent durability. Do you still think the roaches are not built for unarmed combat. They do have knifes and guns. @JamieB $\endgroup$ Apr 17, 2023 at 14:15
  • $\begingroup$ I assumed maybe the speed and strength of the cockroach vs comparatively weak humans would work, but I have had what you said in mind as they really have little to no natural weapons. They do have knifes and guns though. @Vesper $\endgroup$ Apr 17, 2023 at 14:19
  • 2
    $\begingroup$ What about your first two cockroach combat questions (How high would be the body count? and how deadly would a single cockroach be?) have failed to help you either answer or ask this question? VTC Too Story-Based. There are hundreds of variables that affect body count. "How hard" is anything but an objective question, but objective questions are the point of Stack Exchange. The essence of subjective is "subject to the conditions of the story." (*Continued*) $\endgroup$
    – JBH
    Apr 18, 2023 at 3:11

2 Answers 2


At 1 inch tall the humans will be too big for a single roach to handle 28 people

At 1" tall, these people will have 1/373,248 of their original mass. For a typical 180 pound human, this would be around 2.2 grams, a German cockroach only has a mass of about 1.1 grams. So we're talking about a situation where a single creature single handedly takes out 21 out of 28 other creatures, where the single creature is half the weight of each of the other individuals, many of whom would be focusing on escaping after the first few of them fell. This stretches the limits of imagination.

  • $\begingroup$ How many do you think he could realistically take down? Would 2 others do the trick? $\endgroup$ Apr 17, 2023 at 19:04
  • $\begingroup$ Plus all those wee humans will be wielding hair pins pole arms, needle swords, bits of string and match sticks. They'll have that cockroach hog tied, it's mandibles jammed open and cut to pieces in no time! $\endgroup$
    – elemtilas
    Apr 18, 2023 at 1:04
  • $\begingroup$ @elemtilas Note that in the OP, #2 says that the humans have no weapons. $\endgroup$
    – Mathaddict
    Apr 18, 2023 at 14:08
  • $\begingroup$ Yeah,no. They are unarmed, plus I think those are too big and heavy for 1 inch humans to use, let alone the fact human are slowpokes compared to most cockroaches. I was thinking they probably get guns or something later down the line. Well there is unarmed combat by like one a few peeps, but that is not relevant here. @elemtilas $\endgroup$ Apr 18, 2023 at 20:56
  • $\begingroup$ Yeah, they are unarmed at that moment. But for real, what do you think would be a reasonable bodycount for 1? 1? 2? 3? More? None? @Mathaddict $\endgroup$ Apr 18, 2023 at 20:58

They're too blind and clumsy

Cockroaches, while fast, have (by human reckoning) exceedingly poor eyesight, range of controlled motion, and accuracy of movement.

A cockroach's forward-facing 'eyes' are simple ocelli (basically glorified light sensors), and while its larger side eyes are more capable of resolving detail, the natural aberrations of its lenses at the outer edges mean that its vision in front of itself is severely constrained. They have no capability for depth perception.

Insects in general don't have the same level of dextrous muscle control as humans. When self-cleaning, it can take them multiple attempts to target the correct spot. They also have to demarcate their bodies into separate sections, each of which is cleaned by a different limb.

enter image description here

Additionally, they have much less joint mobility, flexibility, and control than humans, and less controlled range of motion. e.g many species of cockroaches struggle to flip over if on their backs.

As a result, it is unlikely a cockroach would be able to accurately perceive a human head, much less aim well enough to knock it off, and humans, with their considerably better agility, perception, flexibility, should have no trouble evading the creatures.


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