Stingrays are marine animals known for their flat bodies and undulating pectoral fins as they glide through ocean waters. These cartilaginous fish, closely related to sharks, inhabit diverse aquatic environments, from shallow coastal areas to deeper ocean regions. Their unique anatomy sparks curiosity, especially concerning their feeding structures, which differ from many other fish species.
Stingray Mouths: No Traditional Teeth
Stingrays do not possess the pointed teeth commonly associated with predatory fish like sharks. Instead, their mouths are equipped with specialized dental plates adapted for their specific diet. These structures are not separate, sharp teeth but flattened, calcified formations that create a continuous, pavement-like surface within their jaws. This dental arrangement is composed of modified placoid scales, similar to the dermal denticles found on a shark’s skin.
The plates include dentin and an enamel-like outer layer, providing a robust, durable surface. Depending on the species, a stingray may have two or four of these plates, positioned in their upper and lower jaws. These plates are designed primarily for crushing and grinding, rather than biting or tearing. Stingrays continuously replace their dental plates throughout their lives, ensuring their crushing surfaces remain effective. Occasionally, male stingrays temporarily develop sharper teeth during mating season to grip females, which then revert to their flat form after breeding.
Specialized Feeding: How Stingrays Eat
The dental plates of stingrays are well-suited for their bottom-feeding lifestyle. These powerful structures enable them to efficiently crush the hard shells of their prey. Their diet primarily consists of bottom-dwelling invertebrates, including clams, oysters, crabs, other crustaceans, marine worms, and mollusks found buried in sandy or muddy substrates.
Stingrays employ several foraging techniques to locate and consume their meals. They often sift through sediment or dig into the seafloor using their flexible pectoral fins. A common method is “tenting,” where the ray presses its pectoral fins against the substrate and raises its head, generating a suction force that pulls prey from beneath the sand directly into its mouth.
Since their eyes are on top of their bodies, their mouth is on their underside, an ideal adaptation for feeding on the seafloor. To detect prey concealed in the sand, stingrays utilize specialized electroreceptors called ampullae of Lorenzini, which sense the faint electrical signals emitted by living organisms. Their jaws are flexible, allowing for chewing motions in multiple directions, aiding in processing hard-shelled prey.