Keel
Definition
The keel is an enlarged ridge on the sternum (breastbone) that anchors the powerful pectoral muscles penguins use for swimming. In flying birds the keel supports flight muscles, but in penguins the same structure has been repurposed for aquatic locomotion. A penguin's keel is proportionally larger than in many flying seabirds because the pectoral muscles must generate enough thrust to propel a dense, streamlined body through water. This skeletal feature is a key piece of evidence that penguins descended from flying ancestors.
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Frequently Asked Questions
What does keel mean in penguin biology?
The keel is an enlarged ridge on the sternum (breastbone) that anchors the powerful pectoral muscles penguins use for swimming. In flying birds the keel supports flight muscles, but in penguins the same structure has been repurposed for aquatic locomotion. A penguin's keel is proportionally larger than in many flying seabirds because the pectoral muscles must generate enough thrust to propel a dense, streamlined body through water. This skeletal feature is a key piece of evidence that penguins descended from flying ancestors.