The lynx, in our eyes, is a wildcat of unthreatening dimensions. It has tufted ears and a spotted coat. The ruff beneath its chin grows in two bunches, recalling the beards of the men of Byzantium. Its stubby, black-tipped tail makes you think it might have lost a more splendid appendage to a fire. The lynx is mostly solitary, and rarely seen. Its dens are found in forests and between boulders, in Europe, Asia, and North America. The bobcat, a species of lynx, lives in the Catskill Mountains—do you hear cat-skill or cats-kill?—hunting little mammals. Another species, the Iberian lynx, was once the rarest cat on Earth: For a time, there were just 94. Today, more than 500 Iberian lynxes live in Portugal and Spain; bringing them back cost more than $76 million.
The lynx, to a louse, is—but doesn’t this sound like the start of a Jorge Luis Borges story? To a louse a lynx is a meal of preposterous magnitude. Also, habitat. Unlike, say, fleas—ready defectors—lice are loyal. Each species tends to colonize a specific type of animal. And almost every furred creature is populated by a unique kind of louse. Though bobcat lice are strangers to the lice that roam lynxes in Romania, they have some similarities: They have dozens of young but care for none; they emit no noise. Some lice suck, and these tend to be homebodies (they live at the base of a hair). The Iberian lynx’s louse, by contrast, likes to chew. It wanders the lynx, stopping to lever up flakes of skin and create tiny blood lagoons from which to drink. It is intrepid, a description further justified by the fact that it is eyeless. The louse has no idea what its lynx looks like, and the lynx cannot see the louse either—though the lynx feels the louse acutely.