Carl Stephenson's detailed adventure story "Leiningen Versus the Ants" was first published in Esquire magazine in 1938, but has since been reprinted in many anthologies.
The owner of a Brazilian plantation, Leiningen, listens to an agitated District Commissioner warn him about an approaching army of ants, “every single one . . . a fiend from hell.” When Leiningen is adamant that he will not abandon his land, so official throws up his arms, insisting that the plantation owner does not understand that the ants are an elemental force, an act of God. Nevertheless, certain that he will prove more than a match for the “irresistible” ants, Leiningen contends that he will defeat this elemental force with his intelligence.
After the commissioner's departure, Leiningen assembles his loyal and trusting men and informs them of the advancing ants. At noon on the second day, their approach is announced by a terrorized stampede of all sorts of animals including jaguars and pumas, tapirs, monkeys, rodents, snakes, and lizards.
At the end near the house and outbuildings, Leiningen has had a weir, or dam, constructed to divert the water. And while the ditch seems to be adequate security, Leiningen still exercises precautions such as moving the cattle and transporting the women and children to the compound of houses and outbuildings. Then he checks the inner moat, a smaller ditch in which pipes of petrol can flow.
As he surveys his property, Leiningen discerns “the darkening hem” that mows the countryside. The workers scream and curse, then relapse into silence. Even Leiningen hesitates, but he vows to fight both “death and the devil” as the hostile army of ants marches toward him.
Having reached the ditch, the ants break into two wings expecting to find a place to cross, an action that indicates their thinking abilities. After the ants reach the end of the ditch, they somehow communicate to the southern front.
Leiningen hopes that they may be persuaded to withdraw from his plantation. However, the ants cross by letting ones who have drowned act as stepping stones for the others. Fortunately, not all attempt to cross at once. Still, Leiningen feels the threat of a gruesome death.
He sends one of his herdsmen to the weir to have the river dammed more strongly. To increase the speed and power of the water coming into the ditch, a second peon is sent to bring spades and petrol sprinklers; a third is sent to the point of the offensive.
By the time reinforcements reach Leiningen, the ants are halfway over. As the war between the “act of God” and Leningen’s brain reaches its climax, the peons dig up to the edge of the bank, hurling dirt and sand into the midst of the hostile ants.
The ants' offensive is to attack with an ever-widening front, an action that poses an overwhelming danger to the limited number of men. When one man does not draw his shovel back quickly enough, the wooden handle swarms with scurrying insects that cover his body. Screaming, the frantic peon writhes in pain.
In an effort to control the situation, Leiningen shouts, “Into the petrol, idiot! Douse your paws in the petrol.” While others attend to him, an old Indian medicine man gives him a drink he prepared before.
Distracted by the men's actions, some of the ants turn away from the ditch. Eventually, Leiningen's plan of flooding the ditches works, carrying off masses of ants who scurry up the slope to safety.
While this retreat causes the Indians to celebrate, Leiningen remains unmoved because he knows the return of the ants after dawn is probable. So he has his men camp along the bank for the night while others patrol the ditch with headlights from vehicles and electric torches.
At dawn a rested Leiningen rides along the edge of the ditch, viewing a "throng of beseigers." As he studies the wide, swift-flowing passage of water between the ants and the plantation, Leiningen believes the battle is nearly over. But as he rides along the eastern and southern sections of the ditch, he discovers that the ants are gnawing through the stalks of lianas, dropping leaves steadily onto the ground.
Leiningen feels a sense of foreboding as the ants use leaves to carry other ants across the ditches. And when he observes a pampas stag blinded and reeling from the torture of a thousand ants, Leiningen realizes with horror that he, too, could suffer the same fate.
Although resolved to send the "vermin back to hell," Leiningen knows now that he has underestimated his enemy and that danger lies at the point of the western section of the ditch turning southward where the power of the current has put the leaves so close to each other that the ants' bridge is almost ready.
He orders a man at the weir to repeatedly lower the water almost to the point that it is gone and then suddenly let the river in to drown masses of ants that enter the ditch. This tactic foils the almost-completed fording of the ditch just in time. Nevertheless, it flings hoards of ants onto the Indians, presaging disaster as a sweating peon shouts, "They're over!"
Wasting no time, Leiningen fires three shots as a signal for the second line of defense. Petrol is sent to the concrete trench circling the house and its outbuildings.
Perceiving that the men are losing hope, Leiningen offers to pay them and send them out on rafts. Yet not a man moves. So their patron orders them to dine while the wall of petrol holds the ants back. At twilight, sentries are posted as Leiningen retires to bed, planning how he will recultivate after the ordeal is over.
Morning finds Leiningen viewing the devastation that a black throng of ants made upon his plantation. Still, their hunger is not satiated; they are headed for the house. To cross the petrol trench, the ants collect shreds of bark, twigs, and dried leaves along with the tamarind leaves used as rafts before.
After his men fill the petrol ditch, Leiningen orders them back, drops a stone to reveal a patch of petrol, and strikes a match; suddenly a towering wall of fire encompasses the garrison as the Indians shout with glee.
Despite this great defeat, the ants persevere. As petrol flows into the second tank, the ants march forward again; again they are burned. A third time, and the ants still continue coming as something blocks the flow of petrol into the ditch.
Seeing the approaching ants, the peons' nerves begin to break and they leap over the north side of the petrol trench; there they are covered by the enemy from head to foot. In their agony, the men fall into the river, where crocodiles and piranhas swiftly finish them.
Desperately, Leiningen searches his mind for one more hope of fighting elemental force with elemental force: It may be possible to dam the great river completely so that the water will overflow into the entire "saucer" of land in which the plantation lies. The ranch house and outbuildings stand upon rising ground, so the foundations are higher than the flooding waters will reach.
Leiningen assembles his men, telling them of his plans to get to the dam. From the Indian medicine man, Leiningen obtains a salve to cover himself; he drinks the medicine administered to the bitten peon at the water ditch. Then he begins his race against death, running with only one thought.
Finally he reaches the weir and grips the ant-hulled wheel. Holding his mouth tightly shut against the ants swarming over him, Leiningen strains to turn and turn until the river pours through. Now he feels the pain of the ants biting his flesh. But he runs back, brushing ants from his bloodied face, squashing them to death under his clothes. He is almost blinded from the bite of one under his goggles; he stumbles and tries to rise.
Suddenly before him he imagines the pampas stag in its death agony: he vows not to die this way and staggers forward. At last, Leiningen leaps through the flames and falls unconscious. The peons rush to him, strip off his clothes, and carry their bloodied, partially eaten leader into the house.
With the ants imprisoned between water and fire, the men are saved. The ocean sweeps the battalions of dead ants away. For a while a deposit of ants try to attain dry land, but they are repulsed back into the flood by streams of petrol.
Inside, Leiningen—the winner of the contest of man versus nature—opens his eyes. "I told you I'd come back . . . even if I am a bit streamlined."