yet another new-to-me dino fact -- medullary bone

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Did you know that modern birds have medullary bone in the bone marrow of the long bones of their arms and legs?  That is to say -- female birds who are getting ready to lay eggs have medullary bone.........

Hard-shelled eggs require a lot of the same calcium carbonate required for strong and healthy bones.  If you are going to lay eggs with nice hard shells, you need a way to come up with the calcium that makes those shells hard, without consuming your own skeleton.

Medullary bone, which occurs in the marrow cavities of long bones, is a way that mother birds store calcium in preparation for laying eggs.  Mother birds then can draw on that calcium in a rush when it's time to put shells on eggs, without jeopardizing their own health and strength.

And -- (you knew this was coming) there is evidence in fossilized dino bones that shows that at least some dinos had medullary bone.

I did not know any of this, prior to this afternoon..........................

Another cool set of facts, brought to you and me by Dino 101.



Because we have heard several times, in class, that they have looked for a trait or behavior in modern reptiles as well as modern birds, I googled for medullary bone in crocodiles.  The first thing in the search results was a study done with alligators,  which found no evidence of medullary bone in alligators.  I didn't read the article carefully, after I learned that the alligators did not have medullary bone, but I believe they concluded that medullary bone evolved after dinos and reptiles split apart, eons ago.

Isn't it totally excellent that I can look up this sort of stuff, in seconds, in the comfort of my own study???

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