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How similar are turtle shells to human ribs? © Daniel Bright

A turtle's shell has a lot in common with your ribs

Published: 08th November, 2021 at 11:00
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We're not ribbing you about this one...

The upper shell of a turtle or tortoise is actually the ribcage. The individual ribs fuse together where they emerge from the spine and extend around the shoulders and pelvis of the animal to form a continuous carapace.


The underside of the shell is a separate piece made from the shoulder girdle and sternum (breastbone). So turtles don’t actually ‘live inside’ their shells, any more than you live inside your own rib cage.

But the shell isn’t made entirely of bone. It’s covered with around 54 plates of horn-like keratin that provide waterproofing and scuff-protection.

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Asked by: Vikram Rathaur, London


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luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.


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