4. But it turns out they do in fact have knees.
Not that you would know it from looking at them waddle.
6. Exhibit B:
This image shows a penguin’s legs bent at the knee.
A penguin’s leg is made up of four bones: a short femur, a knee, a tibia, and a fibula. Their legs just look short and stubby because feathers cover the top parts.
Walking has a higher energetic cost for penguins than it does for most birds. Scientists think this came about as a compromise between movement on land and in water.