for National Geographic News
The giant African snail, originally brought to Brazil as a delicacy for gourmet restaurants, has instead become a major nuisance in the country.
The invasive mollusk—which can measure nearly 8 inches (about 20 centimeters) long and weigh more than 1 pound (500 grams)—is widespread in Brazil, thriving in nearly every state.
The snail is currently at the height of its invasion, experts say, and the its success makes eradication near-impossible.
Silvana Thiengo is a mollusk expert from Brazil's national health organization, the Oswaldo Cruz Institute.
"Raining season starts in November, and that's when they like to [lay] eggs," she said. "The snails will show up more, so we do expect the situation to get worse."
The giant snail, native to eastern Africa, was brought into Brazil as a profitable substitute for the common garden snail, which is used for escargot.
There is no record of when the species was first imported, but an agribusiness fair in southern Brazil in 1988 was probably pivotal in sparking the invasion. (See photos of other invasive species.)
At the fair, people sold kits with snails and brochures detailing how to raise them.
At first the African snails seemed promising for food: They had more meat, grew faster, and were more resistant to disease than the garden snail. The African snail was also cheaper to keep.
Brazilians countrywide began growing the giant snail in their backyards, planning to sell the mollusks to fancy restaurants.
Yet eating escargot is unusual in Brazil, and the few diners who would pay to eat the delicacy were not willing to substitute it for a new species with different texture and taste—and suspicious origin. This resulted in thousands of frustrated people with unwanted snails slithering through their backyards.
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