Spelled cartilage- it is a tough, flexible tissue in the body. Your nose and ears are cartilage.
Cartilage are replacements for bones in sharks, rays, and skates is more flexible and lighter than bones that allows these creatures to move more swiftly in the water and do quick turns.
You shouldn't because it doesn't let your piercing breathe
Collagen fiber is a common fiber found in the lips, and other regions of the face. Collagen fibers are is part of the Hyaline Cartailage.
The fins of sea mammals are actually hands and have bones, tendons, joints, etc, just like your hand except not externally expressed. The tail flukes however are only cartailage.