Cranium
Irregular Bone; part of the axial skeleton (core)
Also known as: Skull, Braincase
Classification
Irregular Bone; part of the axial skeleton (core)
Dimensions
In typical North American deer, the cranium can range from 7 to 12 inches in length. It is characterized by an elongated snout and a broad, rounded back section to house the brain.
Key Features
Look for the long muzzle, the large circular openings for the eyes, and row of complex, ridged chewing teeth. On the underside, you will see a large hole at the very back where it connects to the neck. The roof of the mouth is long and flat.
Similar Bones
The skull of a goat or sheep can look similar, but deer skulls often have a distinct depression or pit in front of the eye socket. Pig skulls are much more sloped and triangular when viewed from the side, with much heavier, thicker bone structure.
Across Species
The herbivore skull is designed for grinding plants. Unlike the short, rounder skulls of carnivores, deer skulls feature a long gap between the front nipping teeth and the back grinding teeth. In birds, many skull bones are fused and filled with air pockets for lightness, while in aquatic mammals like whales, the skull is heavily modified for blowhole placement on top of the head.
Evolutionary History
Over millions of years, the ungulate skull has elongated to accommodate larger grinding teeth and to allow the eyes to be positioned on the sides of the head. This placement provides a wider field of view to spot predators while grazing. The braincase has also expanded over deep time as social behaviors and sensory processing became more complex.
Photography Tips
Take photos from multiple angles: directly from the top, the underside (as seen here), and the side. Place a ruler or a common object like a coin next to it for scale. Use soft, natural light to avoid harsh shadows that might hide the small holes and channels on the underside.