In 1998, at the time of the rat population explosion in Vietnam, restaurateurs were ordered to take feline off the menu and the government outlawed cat exports to China. Trade in other natural rat predators, including snakes, owls and civet cats was curbed as well. In nightly TV broadcasts authorities urged families to keep cats as pets. Some provincial zoos set free their snakes and wild cats. Out in the countryside rat catchers could claim a bounty of up to 1,000 dong (about 10 US cents) for every tail they brought in.
Not cats, but more owls and snakes might help to cull the rat pack. Pythons are particularly well suited to the task.
Dozens of diners a month who order feline aren't responsible for the rat population explosion.