What is that little horn on the tail end of the silkworm?
Many types of caterpillars have sharp horns or prickly hairs. This makes predators avoid trying to eat them. Silkworms have a soft growth that looks like a sharp horn, but if a predator tried to eat it, the growth wouldn’t bother them. But the predators don’t know that! The wild ancestors of silkworms that had these growths got eaten less often than those without the growths, so they reproduced more. That’s why modern silkworms have “horns”.
