Last week I wrote about a snail with an iron-plated shell that lives around deep-sea hydrothermal vents, where the water tops 750 degrees F and toxic chemicals swirl. They’re about as close to hell as you can get on Earth. But down in Antarctica, there’s a polar-opposite (yeesh) ecosystem of brutally low temperatures, damn near 28.4 degrees F—the freezing point of seawater.
Yet even there, life flourishes. And one group of fishes, the notothenioids, swims in those frigid waters nearly carefree, thanks to very special blood loaded with antifreeze. Some of these fish have even done away with oxygen-carrying red blood cells altogether, adopting thin, crystal-clear blood that doesn’t get as viscous as the temperatures drop. These fishes are tougher than you. So much tougher than you.