The largest species of stingray known is the short-tail stingray (Dasyatis brevicaudata) and, although its tail is relatively short for a stingray, nothing else is. This species swims through the oceans. In freshwater, another, just slightly smaller species holds the record. The simply named giant freshwater stingray (Himantura polylepis, formerly Himantura chaophraya) is, in fact, one of the largest freshwater fish in the world.
These stingrays get enormous. Records indicate that the short-tail stingray measures up to 7 feet across and 14 feet in length, and can probably get bigger. The giant freshwater stingray is not much smaller, reaching a not unimpressive 6.5 feet or more across. Aside from their size, neither species differs all that much from other stingrays. Both are a subdued muddy brown in color, which renders the fish inconspicuous against the river or ocean floor, with stinging barbs, elongated tails and small eyes on the top of the body.
Habitat and Distribution
The short-tail sting occupies a range of marine habitats, from estuaries to the deep sea bed, in the waters around Australia, New Zealand and southern Africa. Giant freshwater stingrays are found in several large Asian rivers, including the River Ganges in India and the Mekong in Thailand. They inhabit deep water, something that has probably saved the species from the worst effects of overfishing, although the species is still endangered.
These rays are predators, eating diets that consist predominately of bottom-dwelling fish and invertebrates. Like many elasmobranches -- sharks and rays -- these giant stingrays give birth to one or a few live young rather than laying eggs, making them slow to reproduce and so vulnerable to overexploitation. Mature individuals are too big to have many natural predators, but juveniles almost certainly do. Despite the protection offered by their spines and whip-like tails, stingrays are vulnerable to predation by larger fish and aquatic mammals.
Although comprehensive information on populations is lacking, the short-tail stingray appears to be in no danger at present and the International Union for the Conservation of Nature lists it as of “least concern” on its Red List of Threatened Species. The giant freshwater stingray, however, is endangered and numbers are still dropping. The major threats are habitation degradation and water pollution. The giant freshwater stingray also suffers losses from sport fishing, sustenance fishing and capture for the aquarium trade.
- Fish Base: Dasyatis brevicaudata
- The IUCN Red List of Threatened Species: Dasyatis brevicaudata
- Australian Museum: Smooth Stingray -- Dasyatis brevicaudata
- Arkive: Giant Freshwater Stingray
- Animal Diversity Web: Himantura chaophraya -- Freshwater Whipray
- The IUCN Red List of Threatened Species: Himantura polylepis