What would be the repercussions of all non-human animals larger than a mouse dying around 16/17th century in a certain region or across the globe?

Would it mean eventual extinction of humans, as they would not be able to get some necessary nutrients? Or just a regular apocalypse, where few would survive by eating perhaps insects (in addition, of course, to plant based diet)? Would there be a sudden increase insects in the affected regions?

EDIT: I am interested in broad-strokes results and most important effects to the human civilization. Famine, lack of beasts of burden, massive growth of rodents due to lack of predators and subsequent die-off are good examples.

The most important question for me was whether humanity would go extinct or whether it could survive.

The second, broadly speaking, would it be possible for the humanity to recover, even if after a very long time.

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    $\begingroup$ Aren't humans animals larger than a mouse? $\endgroup$
    – sphennings
    Nov 9, 2020 at 20:30
  • $\begingroup$ I would argue the repercussion is the animals dying out, not the other way around. $\endgroup$
    – DKNguyen
    Nov 9, 2020 at 20:36
  • $\begingroup$ Clarified that I am asking about non-human animals. $\endgroup$
    – gruszczy
    Nov 9, 2020 at 21:13
  • $\begingroup$ Thanks for the edit. I've retracted my close vote and deleted my previous comment. $\endgroup$
    – JBH
    Nov 10, 2020 at 1:04
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    $\begingroup$ @JBH: More like a soft suggestion to the querent to clarify what is it that they really want answers for. Are they looking for a reason to generalize mesoamerican style civilizations all over the world? Are they looking for a reason to justify a regression to the stone age? Are the fish and the birds included in "animals"? Where is this horrible plague happening? Because, for example, the Aztecs (who were just fine at the beginning of the 16th century, so they qualify) would be very lightly affected -- they had no domestic animals other than dogs, turkeys and ducks. $\endgroup$
    – AlexP
    Nov 10, 2020 at 1:21

2 Answers 2



Humans are animals, larger than a mouse. (changed by OP)

If you meant to ask "What would be the repercussions of all animals larger than a mouse other than humans dying around 16/17th century in a certain region or across the globe?"

Loss of all food animals.
Loss of all Marine fisheries.
Loss of all work animals. Most notably loss of horses (transport) and plough animals.
Loss of certain classes of materials. No more leather. No more wool. Not even bone. (exceptions, see beefburger, below)

Food, and society:

People would starve in their masses. Agriculture without the ability to plough will produce much less food, transport of crops without any beast of burden will be incredibly problematic. In that era water transport was a bit primitive, but functional. But there were no mechanical transport of any kind yet, so the very best we could do would be hand carts. Equally, plowing could be done by hand, or with human pulling teams. Reinstitution of slavery, anyone? A suitable underclass of humans designated as beast-of-burden?

Humans could survive. Civilization will be set back a couple thousand years, and will have a very hard time recovering with no access to any domesticated animals. Unless you turn your slaves into domesticated animals? Not my sort of world, where subjugated classes take on the roles of horses, oxen and beefburgers.


Loss of all animals larger than a mouse? So. No predators, no raptors. finches are fine, doves, maybe. crows & the like are gone. and... mice are FINE. Insects are FINE. Fortunately so are bats. Phew! Between them and other insects, there will be a measure of control of insects.

With none of their predators remaining, small rodents will go berserk. First a couple seasons of population boom, then complete denuding of the countryside, then utter devastation of a mass dieoff. This cycle may repeat, or may end in a permanent wasteland.

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    $\begingroup$ Very interesting details, thank you @MarvinKitfox! I really like the additional devastation caused by the small rodents. $\endgroup$
    – gruszczy
    Nov 9, 2020 at 21:16
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    $\begingroup$ Also, no fertilizer in the form of manure for the crops. It's not recommended to use human dung to fertilize crops, as it's too prone to cause disease. Depending on the reason for the death of animals, they might be used the first year, but after that it wouldn't work. Also the smell of so many rotting corpses would be horrific. There's only so much "refrigeration" or alternates that can be done on food animals, so while many animals would be preserved, many more wouldn't. At least if it was in a certain area, the animals could be imported, but at high cost of money and lives. $\endgroup$ Nov 9, 2020 at 23:07
  • $\begingroup$ -1 Because 'animal' in normal english (rather than biology) is commonly used to refer to non-human species from the biological animal kingdom. Looking up definitions for 'animal' using 'define animal' on google the second one expresses this meaning "an animal as opposed to a human being". This is totally like someone asking 'Which vegetable is red and juicy?' and you answering with 'There is no such vegetable, because tomatoes are fruits'. $\endgroup$ Nov 10, 2020 at 8:49
  • $\begingroup$ @DavidMulder You're ignoring that the first definition includes humans. Your example is also out to lunch. A more apt example is like someone asking 'Which vegetable is red and juicy?', and someone not being sure if tomato is a valid answer because the OP was not specific enough. $\endgroup$
    – DKNguyen
    Nov 11, 2020 at 0:35
  • $\begingroup$ +1 I hadn't considered the effect the loss of nearly all predators would have on the rodent population, agriculture might be nearly unfeasible just due to storage being nearly impossible. there is very few things humans can build to store grain a rat cannot chew through. $\endgroup$
    – John
    Nov 11, 2020 at 5:54

Regular apocalypse

I'm assuming you are excluding humans themselves from the culling. So we have animals smaller than mice + humans survive the event, all other animals dead.

According to Wikipedia, Vegetarianism can be traced back to three millennia before Christ, and veganism can be traced to the 10th century. I remember reading somewhere that some gladiators in Rome were also vegans, which makes the whole thing older.

Now while it's possible to live on a vegan diet, it's not for everybody - most people who decide to become vegans have to go through a whole process, and the logistics for it are not in place for all people at one given time. For societies that really depend on meat, specially pre-20th century technological level, forcing everyone into veganism will cause dietary shock in most, and there won't be enough quality food for everybody.

It is hard to quantify the effects, but you're basically facing famine. In places like the north pole, where at times your only way to have a meal is to hunt or fish, it may be doom for everyone - otherwise as long as you have arable lands and people know how to grow food, at least some would survive.

By the way, modern nutritionists claim that vegans are vulnerable to b12 vitamin deficiency; which might be prevented with a diet rich in certain algae. Check the wiki above for further details. This means populations living on coasts might be more healthy than populations living on the countryside.

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    $\begingroup$ It's even worse than that. When animals beyond a certain size die out, it tends to mean there was not enough food for them, and unless they were all somehow carnivores that would mean greatly reduced non-animal food. So humans somehow survived only to find no food to eat, animal or otherwise. $\endgroup$
    – DKNguyen
    Nov 9, 2020 at 20:38
  • $\begingroup$ @DKNguyen That is a valid concern but OP did not specify the cause of death. Might be a virus, a miracle or whatever. $\endgroup$ Nov 9, 2020 at 20:40
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    $\begingroup$ There's plenty edible meat in mice, sparrows, clams, shrimp, minnows etc.. No more sunday beef roast for you, but protein is easy enough to come by. $\endgroup$
    – user79911
    Nov 9, 2020 at 20:54
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    $\begingroup$ Thanks a lot! I like the comment @MarvinKitfox - so I guess famine for sure, but not necessarily extinction. Great to hear! $\endgroup$
    – gruszczy
    Nov 9, 2020 at 21:15
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    $\begingroup$ @TheSquare-CubeLaw Yes, I was mostly concerned about the B12 - but if that's not the case, that's great. $\endgroup$
    – gruszczy
    Nov 9, 2020 at 21:15

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