Mandible
Irregular Bone, part of the core skull (axial skeleton)
Also known as: Jawbone
Classification
Irregular Bone, part of the core skull (axial skeleton)
Dimensions
Varies widely from a few inches in small mammals to several feet in large carnivores and marine animals, featuring a sturdy curved body housing a full suite of teeth.
Key Features
Dominated by prominent, conical teeth, a curved lower border, and deep sockets designed to securely anchor powerful roots.
Similar Bones
Upper jaw sections (maxillae), which also contain teeth but are permanently fused to the main skull structure rather than forming a swinging lower hinge.
Across Species
Carnivore jaws feature prominent, dagger-like canines and sharp shearing teeth designed for gripping and slicing meat, whereas herbivores possess flat, ridged grinding surfaces suited for chewing tough grasses and leaves.
Evolutionary History
Over millions of years, the vertebrate jaw evolved from ancient gill arches. In mammals, the lower jaw simplified into a single strong bone per side, with several of the ancestral jaw bones migrating to become the tiny hearing bones inside the ear.
Photography Tips
Take pictures from the side to show the overall curve and tooth profile, and from above or below to reveal the inner structure. Use soft natural lighting and place a coin or ruler next to the specimen for size reference.