Originally written for WildX

How much could you get done in a single breath? Maybe make a bad cup of tea? Now imagine you had to do it underwater. What if your life depended on it? Even the most elite humans can only manage a measly 11.5 minutes and then that’s all they’re doing. Yet, there are some animals that spend almost their entire lives in and on the water, despite not being able to breathe once submerged. These animals live their lives one breath at a time.

Before we get into it, try this, take a few calm breaths, then empty your lungs and breathe in slowly - really slowly - and hold it. Holding? Good, let's continue.

For a long time it was believed that southern elephant seals, found in Antarctica and around the southern coast of Africa, held the record for breath-holding mammals, clocking in at an average of 2 hours. Despite their cumbersome and clumsy appearance on land, they are elegant and efficient underwater, gracefully maneuvering their two- to four-ton bulk. A single dive can take them as deep as 4000ft - the deepest recorded depth is over 7000ft - a depth at which another world unfolds. Known as the “midnight zone”, light is completely absent, and the black water looks like the night sky. Alien-like bioluminescent creatures float and fly past in this haunting seascape, only further perpetuating the illusion of being on another planet – or floating somewhere between planets. How they manage to do this is more surprising than you might think.

Elephant seals have smoker's lung. Really. The toxic gas which accumulates in the lungs of heavy smokers is also found in staggeringly high amounts in the lungs of these deep-sea divers. But, in this case, it's a good thing, because the exact effect that humans try to avoid is what allows seals to dive so deep. At least, that's how the theory goes. The problem, or in this case the benefit, of the colorless, odorless gas (which is naturally produced in small quantities in humans and animals) is that it can bind to red blood cells and thereby slow the delivery of oxygen to the body. Not great when you're just trying to breathe, ideal when you're trying to hold your breath. In addition, the carbon monoxide may have a therapeutic effect on the animals when they shut down select organs to inhibit oxygen usage. Yeah, you read that correctly, they can consciously shut down organs. They’re not the only deep divers with highly specialized organs and abilities.

Sperm whales are giants of the deep (you could comfortably park an entire school bus in the body of an adult whale), expert divers and masters of breath-holding. Easily recognized by their large heads and bulbous foreheads, they have the largest brain of any creature known to have lived on Earth, and their massive heads may hold one of the keys to their diving ability. Floating around in their skulls is a substance called spermaceti, an oily fluid that is still somewhat a mystery to scientists. The earliest theories, if you could call them that, came from whalers, who believed the substance to be sperm. It’s not. But it’s also not entirely clear what it is or what its function is. The leading theory is that it aids in buoyancy, hardening at certain depths to help the whales dive. There’s something else though.

Myoglobin is a protein found in almost all mammals that carries oxygen to the muscles. But, the molecular structure of myoglobin found in sperm whales and other diving mammals is unique. In most animals, it's what makes their muscles look red, in diving mammals the concentration is so high that they appear almost black. And that’s not all, it also carries a higher electrical charge. Now, before you get any ideas, it’s nothing like the charge produced by electric eels, which actually requires an additional, highly specialized organ. Rather, it’s believed to cause electro-repulsion – the same kind you get when you try to push together the poles of two magnets. In myoglobin, it could prevent proteins from binding, which would allow significantly higher concentrations of the protein in the muscles of the diving mammals. What this means in plain English, is that they have the ability to store oxygen in the muscles instead of the lungs, which will collapse at extreme depths. Even with their impressive adaptations, elephant seals and sperm whales can’t match the capabilities of Cuvier’s beaked whales, which can dive at least twice as deep as they do, still on a single breath.

Imagine holding your breath for the entirety of Fight Club. Not a fan? What about Forrest Gump? Jerry Maguire? The Matrix? They all clock in at about 138 minutes – the Cuvier’s Beaked Whale’s record for a single breath hold. And it didn’t just dunk its head, it dove to almost 10 000ft. The pressure at that depth would crush an SUV in a second. Just how they accomplish this is still not entirely known, especially because of the enormous risks that come with survival at such incredible depths – lungs can collapse, and nervous system conditions can cause convulsions.

Part of the answer lies in deep-sea creatures’ unique adaptations, many of which lack rigid physical structure - ideal for the toothless whale. Found around the globe, they swim through seeming nothingness in search of prey which it’s presumed they catch by suction (which in turn is presumably not a nice way to go). This is made all the more impressive when you consider that they are much smaller than sperm whales and other underwater heavyweights, and they make multiple deep dives a day. It’s not always about depth though.

The Nile crocodiles of the Okavango Delta can’t really compete with whales when it comes to deep-sea dives, but they can more than hold their own when it comes to breath holding. Usually they stay underwater for just 10 – 15 minutes, no need to be braggadocious. But they can extend that to over two hours (the longest recorded dive was over six hours long) if they need to, sometimes even longer under specific conditions. How? They have what is arguably the most complex heart in all of nature. This is partly due to the age of species, which has been around for 200 million years, give or take. Plenty of time for evolution to develop the perfect ticker. Like mammals, crocodiles have a four-chambered heart, but they have two aortas where we have only one. The aorta is responsible for carrying blood from the heart to the rest of the body, and they have one coming out of each ventricle (the part that does the pumping). At the entry to their right ventricle they have a peculiar valve that looks a bit like a forked tongue which they can use to redirect the flow of blood. Basically, it allows them to reroute their blood flow, only letting in a small amount of blood to the lungs (to pick up some oxygen), if at all, and continuously cycling the rest around the body. By closing off the lungs, they are effectively only using half of their heart, only channeling blood to a few vital organs. Oxygen depletion is dramatically slowed, and energy conservation is prioritized. Mesmerizingly menacing.

Also found around Africa, but considerably less menacing, are the real champions of the breath-holding Olympics, sea turtles. From the coasts of South Africa to the shores of Indian Ocean islands, the shelled reptiles can hold their breath for an astonishing 10 hours at a time. That’s longer than a direct flight from New York to London. That’s not all the time for every dive though, and when they’re not defending their undisputed title their dive times usually hover around 4 – 7 hours. Enough time for you to drive from Los Angeles to Las Vegas or London to Edinburgh, without taking a single breath on the way. Like crocodiles, they have evolution to thank for their astonishing abilities. Their lungs run almost the entire length of their shells, and they can expand and contract the space between the bottom and top of their shells. On top of that, they slow their heart rates and can store a large amount of carbon dioxide in their blood, slowing their oxygen depletion.

By the way, how are you doing with that breath hold? It’s been about seven minutes…still going? Didn’t think so, but don’t feel too bad, the odds were stacked against you from the start. Thankfully, unless you find yourself in dire circumstances, it won’t affect your daily survival.

From the giant southern elephant seal to the white-toothed terror that is the Nile crocodile, there are countless animals that live their lives one breath at a time. And whether it’s 2 hours or 10, it’s not about how long they can stay under, but what they can do in the space of one breath.