Gentoo penguins are the fastest swimming penguins in the world 🐧 💨 They're also highly intelligent. Watch as they swim together to evade tough predators like this leopard seal. National Geographic Explorer Bertie Gregory spent two years discovering the secret behaviours, surprising intelligence and close-knit societies of penguins from Antarctica to the Galápagos. Much of what he discovered has never been filmed before. Watch Secrets of the Penguins this Earth Day. Tuesday April 22nd from 7pm,