The monarch butterfly (Danaus plexippus) is an iconic orange-and-black flyer that essentially spends its life running on a strict diet of toxic milkweed, making it taste like chemical warfare to any predator brave enough to try a bite.
North American populations are famous for pulling off an epic 3,000-mile road trip down to the pine forests of Mexico, but it is actually a multi-generational relay race—the fast-burning summer crew expires after a few weeks, leaving a specialized "Methuselah generation" to live up to nine months, complete the massive southward migration, and kick off the family drama all over again in the spring.
