Dolphin teeth are not sharp like a knife or a shark’s tooth designed for cutting. Their function is fundamentally different from the teeth of land predators. Instead, their teeth are conical or peg-shaped, designed for grasping and securing slippery prey like fish and squid. This specialized dentition reflects a feeding strategy that prioritizes capture over chewing or tearing.
Anatomy of the Dolphin Tooth
Dolphin dentition is characterized by a unique structure that sets it apart from many other mammals. Most species exhibit homodonty, meaning all their teeth are uniform in shape and size throughout the mouth. This contrasts with the heterodonty seen in humans, where we possess different tooth types like incisors, canines, and molars for varied functions. The typical Bottlenose dolphin, for instance, possesses a large number of these simple, peg-like teeth, usually ranging from 72 to 116 in total.
These conical teeth are embedded in the jaw but lack the complex root structures found in human teeth. Dolphins are monophyodonts, meaning they have only one set of teeth for their entire lifespan. If a dolphin loses a tooth, no new one grows in its place, making the single set permanent.
How Dolphins Use Their Teeth
The primary function of a dolphin’s teeth is not to masticate or chew their food, but rather to grip and hold prey firmly. As active predators, they need to quickly secure fast-moving fish and cephalopods before they can escape. Once the prey is captured, dolphins use their tongue and throat muscles to manipulate the food and swallow it whole, typically head-first.
Dolphin teeth are not used exclusively for feeding, as they also play a role in social interactions. A behavior called “raking” involves a dolphin scraping its teeth across the skin of another to establish dominance or social hierarchy within the pod.
Why Dolphin Teeth Vary Between Species
While the homodont, conical tooth is the standard for most dolphins, significant variations exist across different species, reflecting specialized dietary adaptations. The Risso’s dolphin, for example, has one of the most reduced dentitions, often possessing only a few teeth in its lower jaw, which may number as low as four to 14. This adaptation is likely tied to their diet, as they feed almost exclusively on soft-bodied squid, which they secure using suction rather than a firm bite.
In contrast, the Long-beaked common dolphin can possess an extremely high tooth count, sometimes reaching over 260 teeth, which is believed to help them capture very fast and small prey. The Amazon river dolphin, or Boto, represents a unique exception to the homodont rule, as they possess molar-like teeth at the back of their jaws. These specialized teeth allow them to crush harder prey items like freshwater crabs and small turtles, making them technically heterodonts.
Reading a Dolphin’s Age Through Its Teeth
Dolphin teeth provide researchers with a valuable tool for determining age. As a dolphin ages, layers of hard tissue are deposited around the pulp cavity of each tooth, similar to the annual growth rings found in a tree trunk. These layers are formally known as Growth Layer Groups (GLGs) or Dentine Layering.
Scientists can extract a tooth and slice it open to examine the cross-section under a microscope. By counting the distinct dark and light bands, researchers can estimate the animal’s age with a high degree of accuracy. This process provides important data for population studies, allowing scientists to monitor the health and longevity of dolphin groups in the wild.