Summary:

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.

Rating: 8.00

David Attenborough's Natural Curiosities

Status: Ended

First Aired: 2013-01-29

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Episode Name : Incredible Shells

Airdate: 2017-06-25

Episode Number: 5

Type: regular