In all rodents , a single large pair of incisors is present in both upper and lower jaws, with left and right incisors pressed together to form a sharp chisel. Softer dentine behind the enamel is worn away more rapidly, leaving a thin, sharp, leading edge of enamel. In some cases, including squirrels , a molarized premolar or two is present as well. Order Lagomorpha , mostly rabbits , are small herbivores with slightly less specialized dentition as compared to rodents. Two pair of upper incisors are present, the tiny second pair directly behind the larger first pair.
Canines are absent, and a large diastema is present.
Molars and premolars are not as well adapted as those of many rodents to a diet of coarse vegetation. Their molars have sharp cusps for piercing the exoskeleton.