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