BRIDGETOWN, Barbados — A breed of giant, ravenous snails that first appeared in Barbados five years ago has thrived on the tropical island, destroying crops and prompting calls for the government to eliminate the slimy pests. A nocturnal "snail hunt" last weekend reported finding hundreds of thousands of giant African snails swarming the central parish of St. George, the country's agricultural heartland, where farmers had complained of damage to crops including sugar cane, bananas and papayas. "We saw snails riding on each other's backs and moving in clusters," said David Walrond, chairman of the local emergency response office, which organized...