A beetle's horn is a weapon, not armour — males wrestle rivals right off the tree
Male Hercules beetles grow a long, curved thoracic horn used almost exclusively to pry, pin and flip rival males off tree branches during fights over feeding sites and mates; females and predators rarely see it used at all. Biologists who study horn evolution in beetles have found horn size is driven overwhelmingly by male-male competition rather than defence, and can be so costly to grow that heavily-horned males sometimes trade off investment elsewhere in the body.