Using pigs to find truffles has been illegal in Italy since 1985, because of the damage they caused while rootling for the fragile delicacy, which led to a near collapse of the industry. It’s certainly true that pigs were commonly used in the past; their great advantage is that they don’t need training. Truffles have evolved to smell irresistible (sexually irresistible, as it happens) to various animals, including pigs. The great disadvantage of pigs as trufflers is that they can’t be trained: once they get the scent, nothing will stop them, and they’re more likely to eat the valuable fungus rather than stand to one side obediently while you dig it out. Dogs, on the other hand, can be trained to sniff out truffles just as they would cannabis or explosives, in exchange for a treat and a kind word. Another reason dogs are now used almost exclusively is that human truffle-hunters guard their secret sites from each other, and walking a dog through the woods is more discreet than walking a pig. And, obviously, dogs are easier to transport around the countryside than big, randy sows.