Manta rays are recognizable and majestic animals, gliding through tropical and subtropical waters with wingspans that can exceed 20 feet. Their immense size and wide-open mouths often lead people to wonder about their feeding apparatus. It is a common assumption that such a large creature must possess teeth for hunting or defense. However, these ocean giants eat using a specialized biological system adapted for effortless filtration, completely bypassing the need for powerful dental structures.
The Answer: Absence of Functional Teeth
True manta rays (genus Mobula) do not possess functional teeth for chewing or biting. Their wide, terminal mouth, positioned at the front of the head, is designed purely as an intake scoop to funnel water, not to grip or tear prey.
Some species, like the giant oceanic manta ray (Mobula birostris), have hundreds of tiny, peg-like teeth embedded in the lower jaw. These remnants are vestigial, meaning they are evolutionary leftovers and are not used for consuming food. Instead, males may use these miniature structures during courtship to grasp the female’s pectoral fin for mating.
The Mechanics of Filter Feeding
The manta ray relies on filter feeding to sustain its massive body. This process begins with a pair of unique, paddle-shaped extensions called cephalic fins that project forward from the head. When the ray encounters a patch of plankton, these fins unfurl from their coiled position to create a funnel, actively guiding food-rich water directly into the mouth.
The separation of food from water occurs across specialized tissues lining the gills, known as gill rakers or filter plates. These structures are not like a simple sieve; instead, they employ a sophisticated technique called ricochet separation. As water flows through the mouth, particles of zooplankton, tiny crustaceans, and larval fish bounce off the angled surfaces of the filter plates and are directed toward the esophagus.
Filtered water continues over the gills for oxygen extraction and then exits the body through the gill slits on the ray’s underside. This ingenious system allows the manta ray to process huge volumes of water quickly and without the filters becoming clogged. They consume between 20 to 30 kilograms of plankton daily by swimming through the water column with their mouths continuously open.
Manta Rays and Their Cartilaginous Relatives
Manta rays belong to the class Chondrichthyes, which includes all sharks, skates, and rays (known as Elasmobranchii). These animals are characterized by skeletons made entirely of cartilage rather than bone. This classification places them as close relatives to predatory sharks, whose mouths are typically lined with rows of sharp, replaceable teeth used for hunting and tearing flesh.
The manta ray’s toothless, filter-feeding adaptation is a notable evolutionary divergence within the Elasmobranch group. While many rays, such as the eagle rays and cownose rays, possess pavement-like teeth for crushing hard-shelled prey like mollusks, manta rays evolved to exploit the vast resource of plankton in the open ocean.
The two main recognized species, the reef manta (Mobula alfredi) and the giant oceanic manta (Mobula birostris), both share this unique feeding strategy. Their success demonstrates that powerful teeth are not a prerequisite for becoming one of the largest and most successful fish in the marine environment.