Penguins, quite often when they get out of the water have to get up, high up onto ice. And the only way to do it is for them to swim up which are very, very fast. And then as soon as they come out of the water they have enough momentum, basically, to carry them up onto the ice shelf. The thing that makes that process more difficult is that hanging around in the surface there are things like leopard seals, which will eat any penguins that don't make this transition fast enough. So there's an evolution new pressure on the penguins to get through that boundary as fast as possible, so you'd be swimming as quickly as possible as they go up to the surface. So this is very famous images in the blue planet of penguins swimming and they've always got its trail of bubbles. And everyone's just kind of, yeah, penguins have bubbles. They don't really thought about it. Until a few years ago, the University of Bangor a couple of fluid dynamics is kind of, why is that? What's going on? So they had a bit of a think. And it turns out that what the penguins do is really, really cool. They, before the penguin, if you ever see penguins in the wild or on TV, they're preening. They're constantly preening. The feathers are a most important thing a penguin has because they're its insulation and they're a large part of how high-dynamic it is, how easy it swims through the water. So anyway, before the penguins go down to dive and they can be quite long dives, the penguins will fluff up their feathers and trap gas, trap bubbles underneath. And then they go down and they go hunting for fish. And then it comes time to go back up to the surface and hop out onto the ice past the leopard seals. And so what they do is, as they're starting that swim upwards, they sort of unsluff their feathers and they release bubbles, a coat of bubbles. And what those bubbles are doing is inducing turbulence. They're just like the same reason that a golf ball has dimples. The bubbles are reducing the drag on the penguin. And the penguin that is producing bubbles can travel 50% faster than the penguin that isn't. So it stands a much better chance of getting past the leopard seals now onto the land. So this is brilliant because it's this wonderful interaction of all sorts of things. It's a physical process. The reason the bubbles come out as the penguins swims up is because the pressure is decreasing. The bubbles are expanding, so they can come out of the feathers. They're reducing turbulence and drag, which is one of the most complicated problems in fluid dynamics and the penguins just sort of do it. And it helps them. It changes the ecosystem because the penguins can then survive in conditions they would not otherwise be able to survive in tea. So penguins use bubbles, and I think that's brilliant.