Sharks do not have any bones in their bodies. Instead, their entire skeleton is made of cartilage, a flexible and lightweight connective tissue similar to what humans have in their ears and nose
. While humans have about 206 bones, sharks have roughly 200 to 400 cartilaginous structures, but these are not true bones. The number of these cartilage segments varies by species and can include parts such as the vertebrae, ribs, jaws, and fin supports
. For example, a shark's spine may consist of about 45-50 cartilage segments, ribs about 26-35 pairs, and jaw cartilage 6-8 sections
. This cartilaginous skeleton provides sharks with advantages such as greater flexibility, lighter weight for buoyancy, and the ability to swim faster and more efficiently than bony fish. Some parts of the cartilage, like the jaws, are hardened by calcium salts to provide strength without the weight of bone
. In summary, sharks have zero bones; their skeletons are made entirely of cartilage, with the number of cartilage segments varying by species but generally ranging from about 200 to 400 structures that function similarly to bones in other animals
