What Are Cow Killers (Velvet Ants)?

When I was about seven years old, my mother began nostalgically reminiscing about her own childhood. She told me that her family's yard in rural Alabama had at one point been infested with "cow killers." She described them as gigantic, furry, red-and-black ants which, according to her own grandmother, had a sting strong enough to kill a cow. That night, I had nightmares about ants the size of dogs overrunning my mother's childhood home, biting into cows and killing them.

I hadn't thought about cowkillers much, if at all, since then-- until today. I nearly jumped out of my skin this morning when I saw an ant as large as my thumb in my bathroom sink. It was black and red, with a fuzzy layer of fur all over its body. I knew immediately that this was the "cowkiller," that almost-mythical monstrocity of my childhood.

A bit of research taught me that the cowkiller is better known as the velvet ant. In reality, though, velvet ants aren't ants at all, but a type of wasp. The insect's sting is obviously not strong enough to actually kill a cow, but online reports suggest that it is significantly stronger than an average wasp sting. That century-old country wisdom came in handy-- I handled the velvet ant with extreme caution, gently scooping it into a cup before releasing it outside.

Velvet ants or cowkillers show obvious sex differences. The females-- those mistaken for ants-- are fuzzy, wingless, and brightly colored. The males look far more like ordinary wasps, with wings capable of flight, but they do not have stingers. Females are usually seen running on bare ground in hot weather, looking for insect prey.

The cowkiller's predatory behavior is truly the stuff of nightmares. It's only the insect's relative size that makes it anything short of a monster. The females invade the underground nests of bees and wasps, then lay their eggs on the developing larvae of the prey species. Later, hundreds of baby velvet ants emerge and consume the developing pupae of the other species. The young cowkillers then spin cocoons inside the exoskeleton left behind by their prey.

The University of Nebraska reports that, although capable of delivering a powerful sting, velvet ants are ultimately harmless and should be left alone. So, as much as cowkillers terrify me, I respect them as a species. I was actually glad to come face-to-face with the animal that haunted my childhood nightmares, and to realize that it, too, was simply trying to survive as a part of the unending web of life. Although my research revealed that these large, fuzzy wasps are not endangered or threatened, I'm happy to let the single velvet ant I've encountered to on with its life.