Five years ago, the first stories broke about a mysterious syndrome affecting American and Canadian diplomats in Cuba. Each case began with the victim hearing inexplicable grating sounds that people around them couldn’t detect, which then developed into headaches, hearing loss, vertigo, and even brain damage. New cases began to appear in embassies all around the world, with the most recent reports occurring just last year, and the phenomenon came to be known as Havana syndrome.To this day, we still don't know what might be causing it. Theories range from secret government weapons to the power of mass suggestion, from exposure to harmful pesticides to the sounds of noisy tropical crickets. One of the earliest speculations was that it might be a sonic weapon, since we know that sound can be directed to a single listener without anyone else noticing, and that sound can do just as much harm as it can good. The secret behind Havana syndrome, whether it's an acoustic attack or something else, is still waiting to be uncovered, but sound's potential as a weapon is nothing new. Animals have been shaping soundscapes to their advantage for millions of years and we've used sound as a wartime strategy for just about as long as we've had wartime strategies.This episode’s the first of a three-part series where I’ll be taking a look at how sonic tactics are used by everything from sperm whales to tiger moths, from Bronze Age battles to the now-famous “Ghost Army” of World War II, and just what the future of sonic warfare might hold.We’re all familiar with the roar of a tiger, the howl of a wolf, or the hiss of a snake: animals use sound to not only communicate with each other but with their natural enemies, to warn them away and hopefully avoid a fight. But can animals use sound itself in a fight? The answer turns out to be yes, especially underwater where sound waves can be louder and more destructive than in the air. One such animal is the pistol or snapping shrimp, and I’ve talked about them before. Despite being barely an inch long, the pistol shrimp can create the loudest sound on Earth by snapping its claw to throw a literal bubble of sound at its prey, a bubble that’s as hot as the Sun and louder than a blue whale.The title for the world's loudest animal arguably goes to the sperm whale, and it might also use sound as a weapon. Its clicks, which it uses for echolocation, are 230 decibels, so loud that they can be fatal to a diver who gets too close. Check out this link for a short video from author James Nestor about a diving team's awe-inspiring encounter with a pod of sperm whales, and how one diver found his left hand paralyzed for several hours after reaching too close to one of the clicking whales.https://www.youtube.com/watch?v=zsDwFGz0OkgBeing around a sperm whale who's blasting away at full volume can be deadly for humans, but are their sounds also a weapon that they can aim and fire to stun giant squid? Biologists still aren't sure. For a long time, the answer seemed to be yes, but some more recent studies suggest that might not be the case: perhaps sperm whales are just loud because they're so big. Regardless, as one of the biggest and loudest animals to have ever lived, keeping our distance is probably a good idea.Another cetacean (seh-tay-shan) that definitely uses sound to attack its prey is the killer whale, which hunts just about everything it can eat, from sharks to seals to other whales. When it comes to feeding on large schools of fish, a pod of orcas will often surround them and use slaps of their flukes, and the shock wave the sound makes, to stun the fish and keep them from swimming away. While the fish are left reeling from the blasts, the whales are free to eat as many as they like.Here's a link to a rare underwater recording of such a feeding event, called “carousel feeding,” so you can see – and hear – their tail slaps for...