>If all the African elephants 200 or so years ago could communicate and coordinate, they could more or less take over the world - at least Africa + Eurasia.
The trebuchet would be enough to stop them.
https://en.wikipedia.org/wiki/Trebuchet#Comparison_of_differ...
>Now imagine 100k elephants working together and humanity is armed only with muskets.
Crossbow would be sufficient. Your target is as big as an elephant. Whaling harpoons were also very popular for a very long time.