How many incisors does a groundhog have?

A groundhog has four incisors.

Like other rodents, a groundhog has a pair of incisors in the upper jaw and a pair in the lower jaw. These four front teeth are specialized for gnawing vegetation, roots, bark, and other tough materials encountered while feeding or digging.

Groundhog incisors grow continuously—about 1.5 millimeters per week—so ordinary feeding and gnawing are essential for keeping them from becoming excessively long. Their incisors are unusual among many rodents because they are white to ivory-white rather than the orange-tinted color often associated with beaver or rat teeth.

A common mix-up is to count only the two large lower front teeth visible when a groundhog opens its mouth. The animal actually has two upper incisors as well. The remaining teeth are cheek teeth used for grinding, not incisors. Groundhogs can also use their incisors defensively, although retreating into a burrow is usually their first response to danger.