Why 20% of all drugs are tested on monkeys costing $20,000-$50,000 each, and how noticing hidden business opportunities in plain sight—like monkey breeding, dental billing, and generator servicing—can unlock massive hidden profits. More than 20% of all drugs undergo testing on monkeys, with prices surging from $2,000 to $50,000 per animal after China halted exports, creating a $4 billion annual business for companies like Charles River Labs.