The longest breath ever recorded, in whales

How they do it: The whales have a number of adaptations to help them hunt beneath the waves. They can almost empty and refill their entire lungs in a single breath. When humans breathe, oxygen is taken from our lungs via a protein called hemoglobin in our blood. Whales have hemoglobin, too — but they have a lot more of it. Both also have myoglobin, another oxygen-storing protein, in their muscles. Cuvier's beaked whales have more myoglobin than most diving mammals and far more than humans. "Their muscles are almost black with myoglobin," says Falcone.

The whales have other ways to conserve oxygen: on deep dives, they temporarily shut down their liver and kidneys and pull blood from their extremities. Their ribs collapse and fold, which helps remove air pockets and makes it easier for them to dive. The whales don't need to swim to reach those depths: they just hold their breath and sink into the black.