Thaumetopoea pityocampa is a moth species that is highly destructive to pines and cedars from North Africa to Central Asia. Their numerous white nests high in the pines are a common sight as short winters transition to spring. They’re best known for their behaviour of descending from their nests in meticulously formed lines, but they’re also notorious for their severely irritating harpoon-like hairs – harmful to humans and deadly to pets. In 1916 the French entomologist Jean-Henri Fabre famously described an experiment where he created a ring of these caterpillars that circled a flower pot for seven days. It later turned out that the conditions of the experiment gave them no other choice. Such is life.