Where is an elephant's bone marrow?

Chris - This is a really interesting question. When I was in Africa, I found an elephant's leg bone and they're like a solid piece of rock.

An elephant is so heavy that it needs to have almost solid bone, with no marrow cavity in the middle, because the bones otherwise would not be strong enough to support the elephant's weight.

So an elephant shunts all of its blood formation up into its pelvis, which is also an important place in humans too, but it means its legs are largely solid bone with virtually no marrow in them.

Unlike a human, where most of our blood is made in our long bones - our femurs...