Rabbits possess a unique dental structure that sets them apart from other small mammals. They are classified as lagomorphs, not rodents, a distinction based on their distinct incisor arrangement. This specialized anatomy is an adaptation to their natural diet of abrasive, high-fiber vegetation. Understanding the structure and function of these front teeth is important for owners seeking to ensure the health and well-being of their animals.
The Specific Number of Incisors
A rabbit has a total of six incisor teeth, a number that distinguishes them from rodents, which only have four. The lower jaw holds a single pair of large, chisel-like incisors. The upper jaw features two pairs, totaling four upper incisors.
The defining feature of lagomorph dentition is the small, secondary pair of upper incisors, often called “peg teeth.” These two tiny teeth are situated directly behind the primary, more visible pair. This six-incisor arrangement is a key anatomical trait. When the rabbit’s jaw is at rest, the lower incisors align precisely between the large upper incisors and the small peg teeth.
Continuous Growth and Function
Rabbit incisors are aradicular hypsodont teeth, meaning they lack true roots and grow continuously throughout the animal’s life. This constant growth counteracts the wear caused by their abrasive diet. Incisors can grow rapidly, approximately three to four millimeters per week, requiring constant abrasion to maintain a manageable length.
The incisors function to grasp, slice, and tear fibrous vegetation, preparing it for the grinding process carried out by the cheek teeth. The upper and lower incisors meet with a precise scissor-like action when the rabbit bites. This self-sharpening mechanism ensures the teeth maintain a sharp, beveled edge necessary for cutting tough plant material.
Dental Problems and Prevention
When incisors do not align correctly, malocclusion occurs, a common health issue in rabbits. Malocclusion can be congenital, often seen in dwarf breeds, or acquired due to trauma or underlying cheek tooth disease. If the teeth do not meet properly, they cannot wear down, leading to rapid overgrowth.
Overgrown incisors can curl into the mouth, causing painful injuries to the gums, lips, and soft tissues. Severe overgrowth prevents the rabbit from closing its mouth or grasping food, leading to an inability to eat, drooling, and weight loss. For rabbits with incisor malocclusion, veterinary intervention is necessary, typically involving regular trimming with a specialized dental burr every few weeks.
The most effective prevention strategy is providing a continuous supply of high-fiber hay, such as Timothy hay. Chewing hay encourages the lateral jaw movements necessary for the proper wear of both the incisors and the cheek teeth. Owners should never attempt to trim incisors with nail clippers or scissors, as this can fracture the tooth and lead to severe infection. In cases of chronic, severe malocclusion, a veterinarian may recommend the permanent extraction of all six incisors.