Tuna Fish School Human Engineers in Hydraulics

Underwater robots do a lot of neat things--take photos of underwater volcanoes, track leopard sharks, and explore shipwrecks--but they could still learn a few things from fish. Tuna are built to cruise across oceans, usually at around 2 mph. But they can crank up to 45 mph at the drop of a snack (Michael Phelps races at around 5 or 6 mph, for comparison). And tuna are agile, too, able to whip after fast-turning squids or sardines. They owe their agility, in part, to a newfound hydraulic system that allows them to raise and lower some specialized fins.