Stingrays are marine animals, closely related to sharks, known for their distinctive flattened bodies. They do have teeth, but their dental structure is quite different from what many might expect, designed specifically for their diet and feeding behaviors.
Stingray Dentition
Stingrays possess a unique dental structure well-suited to their diet. Unlike the sharp, pointed teeth of many fish, stingray teeth are typically flat and broad, forming plate-like structures or rows of pavement-like teeth. These teeth are made of modified placoid scales, also found on a shark’s body. Each individual tooth falls into place to create grinding plates on both the upper and lower jaws.
Their primary function is for crushing and grinding hard-shelled prey. Like their shark relatives, stingrays continuously shed and replace their teeth throughout their lives, a process known as polyphyodonty. New teeth constantly develop behind current ones, moving forward to replace older, worn-out teeth, ensuring a continuous supply of functional grinding surfaces. Some male stingray species temporarily develop sharper cusps during mating season to grip females, returning to their flatter form after breeding.
Diet and Feeding Habits
Stingrays’ dentition supports their feeding habits as bottom-dwelling predators. They primarily consume organisms that live on or within the sand, such as clams, oysters, crabs, and other crustaceans and mollusks. Some species also include small fish or squid in their diet.
Stingrays employ strategies to capture prey, often using their flattened bodies and pectoral fins to root around in the sand or mud to uncover hidden organisms. Some can use suction to pull prey from beneath the substrate. Once prey is located, their powerful jaws, reinforced with cartilage, work with their grinding teeth to crush hard-bodied invertebrates. Their mouths are located on the underside of their bodies, which facilitates foraging for buried food. Stingrays also possess electrical sensors around their mouths, called ampullae of Lorenzini, which help them detect faint electrical signals from hidden prey.
Distinguishing Mouth from Barb
While stingrays possess a functional mouth with teeth for feeding, their primary defense mechanism is distinct from their oral structures. The danger associated with stingrays originates from a venomous barb, or spine, located on their tail. This barb is a modified dermal denticle, similar to a scale, and can vary in size and shape among different species.
Stingrays are generally docile and do not typically exhibit aggressive behavior. They use their barb only when they feel threatened, most often when accidentally stepped on or when encountering a predator. When a stingray feels endangered, it can whip its tail, driving the serrated spine into the perceived threat. The barb contains venom, which causes intense pain and can lead to swelling and muscle cramps in humans. The mouth and teeth function solely for consuming food, while the barb serves as a protective measure.