Getting enough oxygen in the water can be hard work. While fish and many other aquatic animals take air directly from the water through gills, other animals find ingenious ways to drag air bubbles down from the surface or trap air around their bodies. But others do it the hard way and hold their breath to dive, before coming up to the surface for air — and then repeat this process again and again.
Some of these animals can stay submerged for staggering lengths of time. But which animal can hold its breath the longest? And what characteristics enable it to do this?
