David Attenborough's Natural Curiosities S4E5: Incredible Shells
- Aired: 2017-06-25
- Time: 19:00:00
- Runtime: 30 minutes
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Overview
David Attenborough investigates two shells that have proved to be winners in evolution: the bird's shell and the hard shell of the tortoise. The ostrich egg is so strong it's possible for a person to stand on it without it breaking – how does the chick break out of this fortress? The evolution of the tortoise shell was for a long time a mystery and this bony box offers a lot more than just protection.