Rats, mosquitoes, bats, cockroaches, leeches, vultures — it’s easy to fear and despise them. But are they all bad? You probably know that rats destroy food supplies and can cause house fires when they gnaw on electrical wires, but did you know their supersensitive noses can help detect tuberculosis or even land mines? Are these conventionally icky critters really public enemies, or do they have merits worth appreciating? Friend or Foe takes a close look at what we dislike ab