The humpback whale is one of Earth's largest creatures, with an average weight of around 40 tons. But as it turns out, this gigantic creature is vulnerable to the toxins of a much smaller living thing: Aconitum delphinifolium, better known as Larkspur monkshood.
Aconitum was on our list of 10 killer plants, and with good reason: it contains both neurotoxins and cardiotoxins. In China, some warriors recognized monkshood's properties as a biological weapon, coating the tips of their arrows in the poison. But in Alaska, the Alutiiq discovered that Aconitum could take down something far larger than a human. Whaling was dangerous business, and Aconitum was a key part of an important hunting ritual. The whalers would mix the toxic flower with human fat — for its spiritual significance — and then apply the mixture to their spears. Even if the spears themselves didn't kill the whales, the toxin would finish the job in just a few days. The dead whales would wash up on shore, and the villagers would be lousy with blubber.