sentences:  In 1965, Gerald Durrell organised a monkey drive in Sierra Leone during a collecting mission for Jersey Zoo (now the Durrell Wildlife Park).The monkey drive was out of season, and not to exterminate monkeys, but in order to capture colobus monkeys.In his book on the expedition, published in 1972, he wrote that 2000 to 3000 monkeys are killed in monkey drives in Sierra Leone each year, including the "two species" of colobus monkeys, which do no damage to cocoa plantations, and were theoretically protected by law.