David Attenborough's Natural Curiosities - Season 4 - Eps 5: Incredible Shells
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.
About David Attenborough's Natural Curiosities

Title: David Attenborough's Natural Curiosities
First Air Date: 2013-01-29
Last Air Date: 2017-06-25
Status: Ended
Rating: 7.156/10 (from 16 votes)
Language: EN
Seasons: 4
Total Episodes: 27
Network: Eden U&W
Genres: Documentary
Production Companies: Unknown
Synopsis
Sir David shines the spotlight on some of nature’s evolutionary anomalies and reveals how these curious animals continue to baffle and fascinate.
Cast

David Attenborough
Self - Presenter