With their round, flat bodies and undulating wings and their close relationship to sharks, which are some of the sea's greatest predators, stingrays may fit some people's definition of “exotic.” Yet stingrays exist worldwide, from freshwater rivers to the open oceans. No matter what habitat they occupy, an analysis of the creatures that they eat and the organisms that eat them suggests the importance of the roles they play in the ecosystems they inhabit.
Although they are widely distributed, stingrays prefer warm waters. Stingrays adapted to saltwater environments live in temperate and tropical ocean zones, including open bays and regions near coastlines.They may be divided into categories depending on the ocean depths they occupy. Pelagic stingrays, such as the manta ray, swim actively through open waters. More common, however, are benthic stingrays like the southern stingray, which swim along the ocean floor and even hide in the sand.
While the oceans are home to a number of stingray species, at least two dozen species have evolved to live their entire lives in freshwater rivers. These species also enjoy warm water; the Amazon River and Florida's St. Johns River are among their habitats. Like many of their saltwater relatives, freshwater stingrays like the Atlantic stingray glide over sandy bottoms. Many display body markings that match patterns of rocks and light visible beneath the river surface.
Ecological Role of Stingrays
Research has established stingrays of every variety as upper-level predators, meaning that they hunt and consume other animals, even those that consume other organisms themselves. Their foods of choice include mollusks, crabs, small fishes, and worms. Although stingrays often are listed as top-level predators, hunted by no other creatures, researchers including Ian P. Jacobsen and Mike B. Bennett at The University of Queensland have urged nuance, as some sharks and large fish eat stingrays.
Broader Ecological Importance of Stingrays
Yet stingrays fill ecological roles beyond consuming other sea animals and serving as their food. Owen O'Shea, a doctoral student at Murdoch University, has suggested that floor-dwelling stingrays unearth smaller organisms as they displace sand, helping other animals find their prey of choice and possibly making stingrays key ecosystem members. Stingrays even have proven essential to non-marine life; many human populations not only hunt stingrays for food but also make clothing from stingray skins.