Reindeer, known scientifically as Rangifer tarandus, are resilient mammals adapted to survive the harsh environments of the Arctic and sub-Arctic tundra. These animals, which are the same species as caribou, possess a range of physical features that allow them to thrive in northern latitudes. Their teeth are precisely configured to process the tough, fibrous, and often abrasive diet of their icy habitat.
The Total Number and Dental Formula
An adult reindeer typically possesses a total of 34 permanent teeth. This count is determined by the dental formula, which summarizes the number of incisors (I), canines (C), premolars (P), and molars (M) in one quadrant (half) of the upper and lower jaws. The formula for the reindeer is I 0/3, C 1/1, P 3/3, M 3/3. This means the upper jaw has seven teeth per side and the lower jaw has ten teeth per side, resulting in the total of 34.
Specialized Ruminant Structure
The arrangement of teeth is characteristic of a ruminant, an animal that chews the cud. Reindeer entirely lack incisors in their upper jaw, a feature common to cattle, sheep, and other members of the Cervidae family. Instead of upper front teeth, the reindeer has a tough, fibrous cushion called the dental pad. This structure provides a stationary surface against which the sharp lower incisors and canines operate.
The lower canines are often modified to resemble the incisors, forming a continuous row of teeth at the front of the lower jaw. This design allows the animal to grasp and strip vegetation effectively. The lower incisors press against the dental pad to shear off plants like mosses and lichens. This specialized dental structure is suited for grazing and browsing on low-lying Arctic vegetation.
Chewing for a Tundra Diet
The back of the reindeer’s mouth contains the premolars and molars, collectively known as the cheek teeth, which are built for extensive grinding. The rough diet of the tundra, which includes abrasive lichens and woody browse, requires powerful tools for processing. These cheek teeth have high crowns and crescent-shaped ridges of enamel on their surface, which increases the efficiency of the grinding process.
The reindeer chews with a sweeping, side-to-side motion of the lower jaw, which works the tough plant material between the molars. This action helps break down the hard cell walls of the plants, releasing the nutrients for foregut fermentation in the stomach. Constant chewing, necessary for rumination, combined with grit and silica in the diet, leads to significant tooth wear over the animal’s lifetime. The strong, flat molars ensure the reindeer can thoroughly process the fibrous material required to sustain its energy needs in the cold environment.