HOGS WILD.

Of all the domesticated animals, none become feral more readily, or survive better in the wild, than the hog. Of all the larger animals, none reproduce as quickly and abundantly as the hog. The combination of the first fact with the second means that the number of wild hogs in the United States--maybe four and a half million, maybe five--is unlikely to go down. The wild hog is an infestation machine. The Great Smoky Mountains National Park, in western North Carolina and eastern Tennessee, has today a population of about five hundred wild hogs. Since 1977, when the park began a policy of trying to reduce the number of its hogs, its hog-control officers have removed about ten thousand hogs. When hunted, wild hogs often become nocturnal. They are as smart as, or smarter than, dogs. A study done in South Carolina found that catching wild hogs in traps required about twenty-nine man-hours per hog. Past a certain point, removing hogs is too expensive and hard on the environment to be worthwhile. Like other places (not including some islands) that have wild hogs, the Great Smoky Mountains National Park has no expectation that it will ever get rid of its hogs.

A maker of fences in the nineteenth century advertised a new kind of fence as being "bull-strong, horse-high, and pig-tight." In fact, as regards pigs, few fences ever are. Pigs root under, wriggle through. They have been getting away since people first domesticated the species Sus scrofa in Asia and the Middle East nine thousand to ten thousand years ago. When archeologists find an ancient pig skull, they try to tell by certain measurements of the upper second molar whether the pig was tame or wild. The original Sus scrofa, the Eurasian wild boar, has a longer snout than domestic swine and thus a different spacing of teeth in the jaw. (The wild boar is also taller, narrower, and rangier, with bristly hairs standing up along its spine, and a straight rather than a curly tail.) Often, though, the ancient pig skull has indeterminate, gray-area molar measurements, and it's impossible to tell which side of the fence the pig was on.

In the United States, the wild hogs with the longest pedigree are descended from ones that escaped from Polynesian Islanders who first brought pigs to the Hawaiian Islands in about 750 A.D. This strain eventually reinvigorated itself by crossbreeding with escapees from later Hawaiian settlers; many places in the Islands have a vexing wild-pig problem today. The first feral pigs in continental North America deserted from the expedition of Hernando de Soto, the Spanish explorer who crossed the Southeast to beyond the Mississippi River in 1539-42. Wild pigs that got away from Spanish colonists in Florida survived in the woods and swamps so successfully that today some of their descendants represent the only modern examples of old Spanish breeds that long ago disappeared in domestication.

In frontier times, farmers let their hogs run loose, then collected them with the help of dogs on butchering day. Many hogs chose to skip this event, naturally. After America became rich, circa 1890, sportsmen with money imported Eurasian wild boars to stock hunting preserves. When these animals escaped and crossbred with feral swine, they created a tougher and even better-adapted (some say) feral hog. The fact that wild swine have been living in America for centuries does not dissuade wildlife biologists from referring to them as a "non-native" species. Feral hogs of the species Sus scrofa live on every continent but Antarctica, and also on many islands and archipelagoes. Except in the original range of the Eurasian wild boar, feral hogs are non-native everywhere.

Tame or wild, hogs can eat anything humans can eat, and plenty more. They find many different environments congenial. It is perhaps lucky for the planet that hogs have sebaceous glands that do not produce sweat; consequently, hogs need someplace cool and wet to wallow when the weather is hot. This means that very arid regions seem to be safe from hogs for the time being. The current American style of realestate development--expanding horizontally, taking over rural areas, mallifying farmland, leaving only the soggy places and creek beds and river valleys more or less the same, and then passing ordinances prohibiting the discharge of firearms in the new municipalities--suits the hogs just fine. Plus, once in a while enterprising people who love to hunt hogs go to a swamp down South, live-trap a party of hogs, and transport them illegally north to a woods more convenient to the hog hunters' homes. The recent arrival of wild-hog populations in previously hog-free counties in Illinois and Indiana (among other places) probably came about in just this way, wildlife scientists believe.

In 1982, eighteen states in the U.S. had wild hogs. By 1999, nine more states had reported populations of them. By 2004, wild hogs could be found in twenty-eight states; three more have acquired wild hogs since then. States where there had been hogs all along also saw a sudden growth in wild-hog numbers beginning in the early nineteen-nineties. People who think about wild hogs wonder how far they will expand their range. "The number of states with wild hogs is going to continue to grow," says John J. Mayer, a wild-hog expert and the co-author of "Wild Pigs in the United States: Their History, Comparative Morphology, and Current Status," the definitive text. "We're going to wind up with populations in all fifty states eventually."

Well and good, or (more likely) not; but what you really want to know is "What about Hogzilla?" I understand your concern. The question comes up whenever one mentions the subject of feral hogs. People don't pronounce the name neutrally, either. There's always a pause, a kind of awed emphasis: "But what about this . . . Hog-zilla?!" It's a deeply resonant, latter-day American name: HOGZILLA. I am going to deal with the Hogzilla question now, so it won't be hanging over us.