GNAWING

The name rodent derives from the Latin rodere, which means to gnaw. Rabbits, and especially rodents, have large

Figure 7.8 • Radiograph of chinchilla skull showing incisors, diastema and molars with large tympanic bullae.

masseter muscles that allow them great masticatory and gnawing power. The jaw articulation is loose, creating a rotary movement and enabling it to move forward and backward. This means that when the incisors are in apposition the cheek teeth are not, and vice versa. This facilitates a clear division of labor between the teeth used for gnawing and those used for grinding food (King & Custance 1982; Nowak 1999b, 1999c; Vaughan 1986b, 1986c).