In the 1950s, Hawaii’s Department of Agriculture decided to control giant African snails, which had been introduced two decades earlier as garden ornaments, by importing rosy wolfsnails, which are also known as cannibal snails. The cannibal snails mostly left the giant snails alone. Instead, they ate their way through dozens of species of Hawaii’s small endemic land snails, producing what E. O. Wilson has called “an extinction avalanche.”
