# The Birds and the Bones

**URL:** <https://boards.straightdope.com/t/the-birds-and-the-bones/233798>\
**Category:** Factual Questions\
**Created:** [March 11, 2004, 11:37pm UTC](https://boards.straightdope.com/t/the-birds-and-the-bones/233798 "2004-03-11T23:37:47Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Zordran](https://avatars.discourse-cdn.com/v4/letter/z/ac91a4/32.png) [@Zordran](https://boards.straightdope.com/u/Zordran)\
**Post date:** [March 11, 2004, 11:37pm UTC](https://boards.straightdope.com/t/the-birds-and-the-bones/233798/1 "2004-03-11T23:37:47Z")

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If birds have hollow bones, then how/where do they produce blood?

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**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\
**Post date:** [March 11, 2004, 11:47pm UTC](https://boards.straightdope.com/t/the-birds-and-the-bones/233798/2 "2004-03-11T23:47:57Z")

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Not all the bones are air-filled. The breast bone in particular has marrow in the center. And some bones that have do pneumatic spaces have some marrow toward the ends.