Dec 29, 2025
Uncharismatic Fact of the Day
Most caterpillars don't make noise, which is why potential predators get the surprise of their lives when they go after walnut sphinx moths! The caterpillars of this species produce a high-pitched whistle by expelling air from special openings called spiracles on their abdomen. The sound, combined with thrashing and biting, startles would-be predators into leaving the caterpillar alone.
(Image: A walnut sphinx moth caterpillar (Amorpha juglandis) by Kyran Leeker)
