Ships across the planet rely on sonar to safely navigate the world's oceans. This fascinating technology has revolutionized everything from maritime research to international trade and war -- but, somewhere along the way, experts realized sonar might have a hidden price. Listen in to learn more about sonar's effects on marine animals -- and why, for decades, it was the stuff the world's militaries didn't want you to know. Learn more about your ad-choices at https://news.iheart.com/podcast-advertisers