Centuries ago, when penguins were first encountered by European explorers, they were not thought to be birds but rather a fish-like relative. Subsequent accumulation of knowledge has shown penguins to be an avian species with unrivaled aquatic attributes, owing to a number of evolutionary adaptations: shape change, low drag, ability to regulate buoyancy, and extraordinary surface compliancy from their featheration. They are indeed the most extremely specialized diving bird, having given up flight (which otherwise is hugely advantageous) to the benefit of underwater prowess (such as speed,...