Why Do Babies Have More Bones Than Adults?

A baby is born with around 300 bones, whereas a grown adult has 206 bones. Cartilage, a rubber-like padding that shields the ends of long bones at the joints, is the reason behind this. Babies are born with more cartilage (than bone), but it gradually turns into bone over a period of time through a process called endochondral ossification. This is a vital part of the developmental stages of a fetus and leads to the creation of bone tissue in the body.

As the baby grows, cartilage is replaced by bone matrices. Here, calcium salts (that babies get from their diet) are laid to form hardened bones. This is the reason why adults have fewer bones than babies because, for babies, many small bony segments fuse together to form a single bone.