Penguin Adaptations - A quick look - 15 slides
6 - Penguins collect air in their feathers by preening especially before going to sea, it insulates against the cold. This trapped air helps the penguin swim at top speed by releasing as tiny bubbles which reduce drag, very useful when escaping predators.
Picture used courtesy: Liam Quinn from Canada, under creative commons, attribution 2.0 share-alike licence.