The beaver (scientific name: Castorfiber) is an animal of the beaver family and genus. The body of a beaver is enlarged, with no significant difference between males and females. The head is short and dull, the eyes are small, the neck is short, the limbs are short and wide, the forelimbs are short, the feet are small and have strong claws, the hind limbs are thick and strong, and the tail is large and flat. Nighttime activity, rarely going out of caves during the day, good at swimming and diving, not hibernating, weak self-defense ability, timid, fond of eating tender branches, bark, and roots of various plants. The skull is related to biting trees, exceptionally solid, with well-developed bone ridges and prominent sagittal and herringbone ridges. The nasal bone is wide in front and narrow in the back. The cheekbones are particularly thick. The incisors are chiseled in shape and suitable for biting through branches and trunks.