Both manta rays and stingrays are cartilaginous fish belonging to the class Chondrichthyes, a group that also includes sharks and chimaeras. They are further classified together within the order Myliobatiformes, often referred to as the stingray relatives, sharing a common ancestor and a flattened body structure. Despite this close evolutionary relationship, the two groups exhibit profound differences in their anatomy, behavior, and size. This article will clarify the significant biological and ecological differences between the broadly defined group of stingrays and the specific species known as manta rays.
Classification and Overall Scale
The taxonomic relationship is one of inclusion: manta rays are a specific, highly evolved type of ray, while “stingray” is a much broader, general term. Manta rays belong to the genus Mobula within the family Mobulidae, sometimes referred to as the devil rays. This family contains only a few species, including the giant oceanic manta ray and the reef manta ray. In contrast, the term “stingray” encompasses several families within the order Myliobatiformes, such as the Dasyatidae (whiptail stingrays) and Urolophidae (round rays), totaling over 200 species.
The size difference is perhaps the most obvious physical contrast. Manta rays are the largest rays in the world, with the giant oceanic manta ray (Mobula birostris) reaching a disc width, or “wingspan,” of up to 23 feet (7 meters) and weighing nearly 3,000 pounds. Most species of stingrays are significantly smaller, often measuring only a few feet across. However, some, like the short-tail stingray, can grow to almost 7 feet wide and weigh over 770 pounds, and stingrays also include the smallest rays, measuring less than four inches across.
Distinctive Body Features
The most telling anatomical differences are found on the front of the body, particularly the head and mouth placement. Manta rays possess a wide, terminal mouth positioned at the front edge of their head, designed for continuous, ram-style filter feeding. Flanking this mouth are two prominent, horn-like extensions called cephalic fins, which funnel plankton-rich water into the mouth. The body disc of a manta ray is typically wider than it is long, giving it a distinct diamond or triangular shape.
Stingrays, however, have a mouth located ventrally, situated on the underside of the flattened body. This placement is adapted for bottom-feeding, and their strong jaws are often equipped to crush hard-shelled prey like mollusks and crustaceans. Stingrays completely lack the cephalic fins seen on manta rays, and their body disc tends to be rounder, oval, or kite-shaped. While both rays have pectoral fins fused to the head to form the disc, the manta ray’s head projects forward beyond the disc, whereas a stingray’s head is fully enclosed by it.
Feeding Habits and Movement Patterns
The distinct body features correlate with the animals’ different feeding habits and preferred habitats. Manta rays are obligate filter feeders, meaning they must constantly swim with their mouths open to push water over specialized gill plates to collect vast amounts of zooplankton. Because they are always moving to feed, manta rays are pelagic species, inhabiting the open ocean and water column. Their movement is often described as graceful, appearing to “fly” through the water with slow, deliberate movements of their large pectoral fins.
In contrast, most stingray species are benthic, meaning they live on or near the seabed in coastal and shallow waters. Their diet consists of small invertebrates, including worms, clams, and shrimp, which they actively hunt or scavenge from the sediment. Stingrays use their flat bodies to glide close to the substrate, frequently burying themselves in the sand or mud to conceal themselves from both predators and prey. This bottom-dwelling existence is reflected in their ventral mouth and their generally subdued movement patterns compared to the open-water manta ray.
The Presence of a Tail Barb
The most recognized difference that gives the stingray its name is the presence of a tail barb, a feature entirely absent in manta rays. Stingrays possess one or more serrated, venomous spines located near the base of their long, whip-like tails. This barb is purely a defensive mechanism, used to strike out when the animal feels threatened, such as when it is accidentally stepped on. The venom delivered by the spine can cause excruciating pain and, though rarely fatal to humans, can inflict a serious wound.
Manta rays, despite being closely related to stingrays, do not have a venomous barb on their tail. While they do have a tail, it is relatively short and slender and serves no defensive function. Their defense relies instead on their tremendous size, their ability to swim quickly, and their intelligence, as they have one of the highest brain-to-body ratios of any fish. The absence of a stinger and their plankton-feeding diet makes manta rays harmless to humans, contributing to their reputation as the “gentle giants” of the sea.