Incisors (from Latin incidere, "to cut") are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below. Function In many herbivorous or omnivorous mammals, such as the human and the horse, they're adapted for shearing sharply. In cats, the incisors are small and don't do much; biting off meat is done with the canines and the carnassials. In elephants, the upper incisors are modified into curved tusks, just as is the case with Narwhals, where norm… (More on Incisor)