What if your bones were made of cartilage?

children have a lot of cartilage compared with adult bones. As a result, the bones can grow more easily, and this is why children are, in part, so flexible. read more

Not only this, bone’s strength and density helps protect us. Imagine a skull made of cartilage, it wouldn’t protect your brain at all. Basically, because cartilage is not rigid, or dense enough, and it won’t provide adequate support, it’d be pretty useless to have it replace bones. We’d have difficulty living. Eventually, Everyone Dies™. read more

But because their skeletons are made of cartilage much of their early fossil record is poor. Cartilage is a rubbery tissue that forms the framework for bones to ossify (harden) upon. It’s why babies have rubbery legs when they begin to walk, as the bones haven’t fully ossified around the cartilage cores. read more