• Choose a category
• All
• Classic-Fiction

By Root 455 0

Darwin thought of as “nature red in tooth and claw” (though it was Tennyson who put it that way; Darwin couldn’t have been that concise if his life depended on it). Out here in the desert, “tooth and claw” means prickly-pear spine and rattlesnake fang. My dog Jessie would often run congenially with small packs of coyotes, until she came within a stone’s throw of the house. Then, brought up short against the sight of which side her bread was buttered on—which is to say, me—she would whirl around and make a big show of chasing her erstwhile friends out of the territory. I watched this happen dozens of times. One could argue conflicting genetic paradigms, or one could argue dog chow. Either way, Fido is an infidel.

It could be worse. Years ago as a graduate student I helped do a study of desert pupfish—a small, unglamorous species whose mating behavior is so opportunistic it would make Lolita blush. Pupfish live in ephemeral streams where populations fluctuate fairly drastically. When females are scarce, the male will hunt down a mate and swim faithfully by her side, for richer or for poorer, monogamous as Bob Cratchit. But when the tide turns and there’s a surplus of females, the model-husband pupfish becomes a bantam-weight macho terror. He puffs out his little blue fins and claims a patch of river bottom as his private singles scene, performing all manner of gyrations to lure in the babes, who eventually do meander in to lay their eggs. Possibly they are rolling their eyes, muttering to one another about midlife crisis and the trophy wife. Darwin was right; nature is no picnic. It’s an office party.

But it’s not fair to cast this as a bad-boy business; females are no consistent models of fidelity either. Female elk are known to copulate with many males in the same day—and that’s hardly the worst that can happen. The hills are alive with black-widow stories. A female praying mantis rewards her husband’s conjugal exertions by eating his head; basically, that is their prenuptial agreement. And octopus mating, in its own special way, eclipses the tawdrily famous Bobbitts: the male octopus does not come equipped with a penis so he’s obliged to offer his girlfriend a tough little packet of sperm (some valentine, that) by grasping it in a tentacle and shoving it down her breathing siphon. She responds to his overture by attempting to rip him apart. “These matings may be so violent,” writes Robert A. Wallace in a forthright account, “that if the male has managed to insert his arm into the female’s siphon, it may be literally torn from his body. After such an encounter, the female can be seen swimming alone, bearing the grisly memento of a previous coupling.”

In a disenchanting revision of some cherished folklore, biologists are discovering that monogamy is rarer than unicorns in the animal world. Many species touted as mating for life—swans, bluebirds, Australian fairy wrens—are turning out to be hardcore sneaks. The tools of molecular genetics, similar to the tests used in human paternity suits, have shown that in the nest of the average fairy wren, one egg in five is sired by another wren’s mate. Among all songbirds that have been examined in this way, the count is closer to one in three. It turns out the bluebird of happiness wrote the book on free love.

Our culture counts fidelity as a virtue, but where reproduction is concerned, it’s more of a strategy. Monogamy is most likely to be practiced by creatures who have such pathetically helpless or numerous young it takes two frazzled parents to bring them to the self-supporting stage. Think of it as Darwinian family values: if a mate abandons the family, only to leave behind starved kids and nary a gene passed on, he or she is a biological dead end. So, for species in which the parenting demand is extreme, the biological directive that survives through the generations is the gene that sings out, “Be it ever so humble, there’s no place like home.”

This trend, predicting less promiscuity among species with a high parenting demand, bears out pretty well. Birds have the daunting