25/07/2026
"Small Creatures, Big History" — Pests That Shaped the World
The Rats That Brought Down Empires 🐀
History has a warning for us, and it's squeaking.
The Black Death killed up to half of Europe in the 1300s — not because of "bad air," as people believed then, but because of rats. Fleas fed on infected rats, then jumped to humans when the rats died off. One tiny courier, one bacterium, and a third of a continent gone.
Fast forward to 2026: Western Australia and South Australia are facing mouse numbers experts say could rival the catastrophic 2021 plague — with mouse numbers described as "about as bad as it can be" in parts of WA. Normal populations sit around 5–10 mice per hectare. Plague level is 800–1,000+.
We're not looking at Yersinia pestis this time. But mice at plague densities already spread bacterial infections like leptospirosis and yersiniosis — plus the very real toll of destroyed crops, contaminated food stores, and homes overrun room to room.
Rodents alone don't cause pandemics. But when their numbers explode, disease follows close behind — and by the time anyone connects the dots, it's often already spreading.
This is Part 1 of a series on the tiny creatures that changed the course of history. Next up: the insect that starved empires. 🦗
