Science: Nutria Nuisance

My family never had an animal menace like this, said British Farmer Benjamin Banham, whose forebears have been tilling the soil near Great Yarmouth for 500 years. “Last fall they cleared out seven acres of my kale and 40 tons of swede [a kind of turnip grown for cattle fodder].” In Burgh Castle, after trapping 460 of the same varments that ate Banham’s kale, Farmer John Berry was near despair: “If they carry on the way they do,” said he, “they’ll be master of the land in three years.”

Britain’s newest animal menace is a big (larger than a muskrat), large-toothed South American rodent called the coypu (Myocastor coypns), better known as the nutria.* Already the coypu has overrun an estimated 40,000 acres in Norfolk, Sussex and Essex counties, and is munching its way inexorably northward. Its appetite is inexhaustible, and by no means limited to farm crops: a Great Yarmouth farm wife recently complained that coypus were boldly gnawing her window frames, and in some East Anglian river towns, coypus have been known to free boats from their moorings by chewing through the lines. The National Farmers’ Union sets England’s coypu population at 250,000 to 1,000,000—an estimate necessarily vague, since coypus are active breeders (about three litters a year) who do not stop to be counted.

The coypu reached England in 1927 from Argentina, imported by several East Anglian farmers who wanted to cash in on the market for nutria coats. Then one stormy night ten years later, a strong wind blew down the pens on the nutria farm of P.E.T. Carill-Worsley in East Anglia, and some eight animals escaped. The wild coypus in England are descendants of those first escapees.

Since the coypu’s natural predators (alligators, crocodiles and certain types of foxes and eagles) are all back in South America, the animal has flourished in East Anglia’s bogs and fens. Commercial trappers are not interested in its fur: the nutria vogue in Britain declined some years ago. A few British restaurants serve coypu (whose taste resembles veal), thoroughly disguised as “Argentine hare.” But the coypu’s only real enemy is England’s furious farmer who, prevented by law from using poison—which would also kill off harmless animal life—prowls the marsh with trap and gun. “There’s no trouble catching them,” says E. A. Ellis, secretary of the Norfolk Naturalists’ Trust. “The coypu is mentally slow. Once caught he just waits for death, not fighting but moaning. In one area we killed 40,000. But that’s only a fleabite’s worth. There are just too many of them.”

* So named by the early Spaniards, who thought the coypu was an otter. “Nutria” is Spanish for otter.