What does a rat skull look like? - briefly
A rat skull is small and elongated, featuring a narrow triangular braincase, pronounced outward‑flaring zygomatic arches, and continuously growing forward‑projecting incisors. Its total length is roughly 2–3 cm, with short nasal bones that create a blunt snout appearance.
What does a rat skull look like? - in detail
A rat skull is a compact, elongated structure measuring roughly 25–30 mm in total length for an adult brown rat (Rattus norvegicus). The cranium is low and broad, forming a rounded dome that tapers toward the posterior. The nasal bones are short, creating a blunt snout; the premaxilla bears a single large incisor on each side, which projects forward at a 90° angle and lacks enamel on the front surface. Behind the incisors, the maxilla and mandible contain three molar‑premolar teeth on each side, arranged in a 1‑0‑3 dental formula (one incisor, no canine, three cheek teeth).
Key anatomical features include:
- Cranial vault: fused frontal, parietal, and occipital bones with a smooth external surface.
- Sutures: prominent coronal and sagittal sutures; the interparietal suture is visible near the occipital region.
- Foramina: large infraorbital foramen on each side of the maxilla, allowing passage of the infraorbital nerve; the auditory bullae are small, located laterally on the temporal bones.
- Orbit: shallow eye sockets with a thin orbital rim; the zygomatic arches are modest and do not extend far laterally.
- Mandible: robust, U‑shaped lower jaw with a pronounced coronoid process; the angular notch provides attachment for the masseter muscles.
The skull’s surface is covered by a thin layer of periosteum and, in preserved specimens, may display a light brown to off‑white coloration. Bone density is high, reflecting the animal’s need for strong bite forces. Variations in size and proportion occur among species and between sexes, but the overall morphology remains consistent across the genus.