Penguins are pretty cool birds and not just because they hang out on giant blocks of ice. In fact many penguins, like the Galapagos penguin, have adapted to a much warmer climate than in the frozen Antarctic.
Penguins don’t do things like other birds. Unlike the chicken that struts along holding its body horizontally, penguins stand straight up when they walk on land. Perhaps that is why penguins are so beloved. When they stand tall and walk around in their two colour suits, they remind us of…us.
Because penguins evolved to feed in the ocean, they became heavy birds. Their bones are not light and buoyant and their wings do not help them fly like other birds. Heavy bones that aren’t bouyant allow them to dive deep for fish.
Their wings are more like flippers and help them swim efficiently. They have a tear drop shaped body, similar to seals and dolphins, and this bit of convergent evolution enables them to swim with less drag. The less energy required to find food means that less food is required for survival. All good when you consider how far these birds must swim for a meal. Yellow-eyed penguins travel 12-20 km from shore to their feeding ground on the sea floor—a 24-40 km daily commute (for more about this see Mattern et al. 2007). When you think about how much energy it takes for us to swim a single kilometre, any adaptation that would make it easier for a penguin to swim is pretty important for survival.