Harbor seals are marine mammals found along coastlines in temperate and Arctic regions of the Northern Hemisphere. They spend their lives both in water and on land, relying on specialized physical attributes for survival. Their teeth are important for acquiring and processing food. The structure and function of harbor seal dentition allow them to thrive in diverse aquatic environments, making them effective hunters of various marine prey.
Unique Dental Features
Harbor seals possess a distinct dental arrangement that reflects their carnivorous diet and aquatic lifestyle. Their permanent dentition typically includes 34 teeth, though some individuals may have 36. This includes incisors, canines, and postcanine teeth, which are a combination of premolars and molars. The dental formula is generally I 3/2, C 1/1, P 4/4, M 1/1, meaning three upper and two lower incisors, one upper and one lower canine, four upper and four lower premolars, and one upper and one lower molar on each side.
The incisor teeth are generally small, though the third upper incisor can be larger and more canine-like. Canine teeth are large and pointed, primarily for grasping. The premolar and molar teeth, often grouped as postcanines, feature multiple cusps. These teeth typically have a large main cusp with one to three smaller accessory cusps located both in front of and behind it. This multi-cusped design distinguishes their dentition from many terrestrial carnivores, which often have more complex occluding surfaces for extensive chewing.
Teeth and Diet
The specialized dentition of harbor seals is directly adapted to their diet, primarily consisting of fish, but also including crustaceans, molluscs, and cephalopods. Their pointed, sharp front teeth, including the incisors and canines, are suited for grasping and tearing prey rather than chewing. This design is effective for securing slippery, live prey in an aquatic environment.
Harbor seals typically swallow prey whole or tear it into manageable chunks. The multi-cusped postcanine teeth crush shells and crustacean exoskeletons. This allows them to exploit a wider range of food sources beyond soft-bodied fish. Their teeth enable efficient capture and consumption, supporting opportunistic foraging habits that vary seasonally and regionally based on prey availability.
Dental Development and Wear
Harbor seal dental development begins before birth. Deciduous, or “baby,” teeth are present in pups but typically shed either in the womb or soon after birth. This ensures permanent adult dentition is fully developed and functional by the end of a suckling period, usually around four to six weeks of age. This rapid development prepares young seals for independent foraging at an early stage.
As harbor seals age, their teeth experience wear from constant use in capturing and processing food. This wear can manifest as attrition and abrasion, impacting tooth surfaces. The degree of dental wear can indicate a seal’s age. In some cases, intense wear on anterior teeth can lead to pulp exposure. Such wear patterns and associated dental issues provide insights into an individual’s diet and overall health throughout its lifespan.