How does a birds bone help it fly?

Answer

It is said that birds have no marrow in their bones, which allows them to be lighter for flight. This is partially true...

The major reductions in weight however comes from the lack of large jaw bones, no teeth because no jaw bones, small skull, and very little tail [bone]. There is no marrow in the bones of birds, but this doesn't make them lighter it makes the bones stronger.

My source (look under "The Bird Skeleton"):

http://www.earthlife.net/birds/anatomy.html#4

Answer

In addition to the above, some birds' respiratory systems circulate air through some of the bones in order to complete the respiratory circuit. Birds do not breathe in and out like mammals. Their lungs act like a bellows to move the air in through their mouth and out through their nostrils. This permits a much greater oxygen flow, which in turn allows their muscles to create the high energy levels needed for flight.

First answer by ID2211977220. Last edit by Zenballwizard. Contributor trust: 9 [recommend contributor]. Question popularity: 37 [recommend question]