Adventures Among Ants - Mark W. Moffett [67]
SLICERS AND DICERS
That night, Caspar and I set up our tents near the park entrance. I shared with him my most memorable moment of the day: watching a mass of Dorylus mayri ants in the midst of a huge swarm raid remove the eyes and limbs of a pair of 3-centimeter-wide freshwater crabs—small, but rock tough. This kind of activity would be difficult for most tropical American army ants, whose plier-like mandibles tear flesh but are incapable of slicing it. Only a few species can manage to consume even a frog; the others have to abandon their vertebrate carnage uneaten.
The mandibles of African driver ants, however, are like sharp scissors, built for severing. I had guessed that might explain why driver ant raids are eerily quiet to those who have witnessed the swarm raids of the New World Eciton burchellii, which are accompanied by the chirp of “ant birds” that snatch prey that has been missed by the ants, the buzz of parasitic “ant flies” that lay eggs on the escapees, and the flutter of “ant butterflies” that feed on the droppings of the birds. In the driver ant raids I witnessed in Africa, these attendants seemed to be missing—perhaps, I hypothesized, because the driver ants would make mincemeat of them. However, I later learned that birds are actually present, but of a species that is quiet and circumspect.4
What, then, of the claims of popular stories, such as the one about Leiningen, that army ants regularly kill and eat vertebrates? Caspar told me that for all his months in the field, the only examples he’d seen of live vertebrates being killed by driver ants were a frog and a litter of helpless “pinkies,” baby mice the size of the tip of a pinkie finger. In Cameroon several years before, I had helped tribal pygmies remove an antelope from a snare that had one flank partially carved away by driver ants. It must have been bleeding and restrained at the time of their arrival, making an easy target. Most records of vertebrate predation in equatorial Africa concern tethered specimens like that, Caspar said. It’s no coincidence that people living within range of driver ants keep their babies on their bodies and let their livestock roam free.
So, exactly how good were driver ants at carving meat? Two days earlier I had conducted an experiment: I gave a rubellus ant colony a fresh lizard kill, dropping its 6-centimeter carcass right on the ants’ trail. They showed no hesitation: in two minutes the body was packed with workers of all sizes trying to pry through its skin. Each stuck one mandible between the scales and squeezed hard; but again and again, the ant’s opposite jaw slid uselessly over the surface. Two hours later the lizard remained unscathed. During the third hour, the ants began to carve off strips of scales, and three hours after that, most of the skin was peeled away. Altogether, it took the ants ten hours to reduce the lizard to a spinal column. An impressive perseverance, though no doubt a thin-skinned frog or pinkie would have been an easier meal.
To a much greater degree than marauder ants, driver ants process food where it’s found—tearing up their prey to the extent that, to quote the coroner in The Wizard of Oz, “she is not only merely dead, she