3 facts
This cartilaginous skeleton is lighter and more flexible than bone, allowing sharks to be incredibly agile predators. It also makes fossilization rare, as cartilage decays much faster than bone.
Despite their incredibly long necks, giraffes possess only seven cervical vertebrae, identical to most other mammals, including humans. Each individual vertebra is simply much more elongated, allowing for their impressive reach.
A newborn baby has around 300 bones, while an adult has 206. Many of a baby's bones are made of cartilage and eventually fuse together as they grow, like those in the skull and spine, forming stronger, larger structures.