Velvet Ant ('Cow Killer')

Dasymutilla occidentalis is one of about 7,000 species of velvet ant (family Mutillidae) — but the name is misleading. Mutillids are NOT ants. They are wasps in which the females have completely lost their wings and evolved a hairy, ant-like body. (Males are fully winged and look like normal wasps.) Female velvet ants are external parasitoids of bees and wasps: they invade other Hymenoptera nests, lay eggs on or inside the developing pupae, and the velvet-ant larva consumes the host. The species is famous for two extreme defenses. First, the sting: female velvet ants carry an unusually long ovipositor used as a sting, with venom that produces intense pain rated 3.0 on the Schmidt Sting Pain Index — Schmidt described it as 'explosive and long-lasting, you sound insane as you scream.' Folklore that the sting could 'kill a cow' is exaggerated but conveys the perception. Second, the armor: velvet ant exoskeleton is exceptionally dense and tough, capable of withstanding compressive forces 11× the spider amounts that kill normal insects. Researchers at the University of California Riverside studied the exoskeleton in 2018 as a model for impact-resistant materials engineering. Velvet ants also stridulate (rub body parts) to produce squeaking sounds when handled.