Diversity from Isolation
By Daniel T. Ksepka
Fossils of early penguin species reveal the myriad paths these birds took from the sky to the sea, and from temperate New Zealand to the frozen Antarctic.
This Article From Issue
May-June 2026
Volume 114, Number 3
Page 176
Penguins are wonders of evolution. From their stiff flipper-like wings to their comically stubby feet, their anatomy is uniquely adapted for wing-propelled diving. Penguins are also one of the most ancient surviving groups of birds. The oldest penguin fossils are about 62 million years old, appearing a scant four million years after the asteroid impact that triggered a mass extinction at the end of the Cretaceous Period.
QUICK TAKE
- The oldest-known fossils of ancient penguins are found in New Zealand. The islands’ remote location and the near-absence of native mammals allowed these birds to thrive.
- Some early penguin species grew to enormous sizes, which may have aided the development of thermoregulatory systems that enabled later species to survive in extreme cold.
- The long and diverse history of penguin evolution informs the need to protect modern species from anthropogenic climate change, overfishing, and habitat loss.
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