Deception in the Animal Kingdom

An EcoChi Vital Abstract

This article was published in September 2019 by Barbara J. King, Scientific American.

Evidence for cooperation and compassion among swimming, flying and walking creatures has captured public imagination. For centuries, scholars of animal behavior overemphasized the role of rivalry and violence among animals. Yet even as we swoon over animal sweetness, there is a risk of that pendulum swinging too far and eclipsing part of the story. Many animals carry out disinformation campaigns aimed at others, within and across species. They mislead, cheat and lie in rampant acts of deception. Cuttlefish are masters of such disinformation. They have the ability to quickly change color. In 2017, marine biologists reported that they had observed a male common European cuttlefish approach a female in the Aegean Sea off Turkey. The female moved away with apparent indifference. The male camouflaged himself against the background for six minutes, leaving the female seemingly unaware of his continued presence. Then, suddenly, he lunged and grabbed her, and the two mated head to head. In an Australian species called the mourning cuttlefish, deception goes beyond camouflage. When a male swims along between a female paramour on the left and a male competitor on the right, he displays two sets of signals containing polar-opposite information. From his left side he issues typical male courtship signals. On his right side, though, he emits the signals typical of a female. To his male competitor, then, this suitor appears to be just another female. Brilliant—and sneaky! A highly vocal bird called the fork-tailed drongo, of the Kalahari Desert in Africa, emits alarm calls on sighting predators. Sometimes this is honest signaling that benefits not only other drongos but also the birds’ neighbors will dive for safety when they hear the drongo’s calls. But other times drongos do something not as honest, even downright obnoxious. For instance, if a drongo spots a meerkat in possession of a particularly winsome food item, the bird may call falsely—in the absence of any predators at all. On hearing the call, the meerkat drops the food and flees to safety. The drongo then scoops up and consumes the food. Any opportunity to up one’s quota of stolen delicacies makes good evolutionary sense for these birds. But the intricacy, indeed the elegance, of animal deception does not depend on conscious intent. The magnificent spider of Australia hunts moths at night using a ball of sticky silk termed a bolas. This spider produces a single strand of silk with a bolas at the end and flings the line at nearby moths. Here is the magnificently Machiavellian part: the bolas gives off a pheromone that mimics the scent of a female moth. Lured by the irresistible odor, male moths flutter close and become ensnared in the sticky silk. Nothing about the spiders’ deception suggests a thought-out strategy. Instead evolution has promoted the behavior because it benefits their reproductive success. More broadly, animal duplicity may be carried out with awareness and sometimes even with emotional gusto. And yet across species—including those animals who deceive in the absence of premeditated intent—the same individuals may act honestly in some circumstances and connivingly in others.

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