Animal Diversity Web

Ge­o­graphic Range

Giant fresh­wa­ter stingrays are found in the large river sys­tems of Thai­land, in­clud­ing the Mekong, Chao Phraya, Nan, Bang Kapong, Prachin Buri, and Tapi River basins. They are also found in the Kin­abatan­gan River in Malaysia, as well as the is­land of Bor­neo (in the Ma­hakam River). (Last and Man­jaji-Mat­sumoto, 2008; Monkol­pr­a­sit and Roberts, 1990; Rain­both, 1996)

• Biogeographic Regions
• oriental
  • native

Habi­tat

This species is typ­i­cally found over sandy bot­toms in large rivers, at depths of 5 to 20 me­ters. Many fe­males are found in es­tu­ar­ies and it is thought that they give birth in brack­ish wa­ters, though the rea­son for this is not cur­rently known. There are no records of this species from fully ma­rine habi­tats. (Marzullo, et al., 2011; Vidthayanon, et al., 2011)

• Habitat Regions
• tropical
• freshwater

• Aquatic Biomes
• benthic
• rivers and streams
• coastal
• brackish water

• Other Habitat Features
• estuarine

• Range depth

  5 to 20 m

  16.40 to 65.62 ft

Phys­i­cal De­scrip­tion

Like other stingray species, giant fresh­wa­ter stingrays are char­ac­ter­ized by their large oval shape and long tails. In­di­vid­u­als have been recorded to reach weights of 600kg and lengths of 300 cm in total length (one third of which was con­tributed by the tail). The tail is very smooth on the dor­sal side, but the ven­tral side has a spine with saw-like ser­ra­tions and an as­so­ci­ated venom gland. Two pelvic fins are found on ei­ther side of the tail, with the pri­mary trait dis­tin­guish­ing males and fe­males being the pres­ence of a clasper on each male pelvic fin. These pe­nis-like struc­tures re­lease sperm dur­ing cop­u­la­tion. This species’ oval shape is formed by the pec­toral fins, which ex­tend an­te­ri­orly to join with the snout. The pec­toral fins con­tain 158-164 pec­toral ra­di­als, which are small bone-like struc­tures that sup­port the large fins. Over­all, the body is rel­a­tively flat. The mouth is lo­cated on the un­der­side of the disk and is com­prised of two jaws filled with small teeth, and lips cov­ered with small papil­lae, which are sim­i­lar to taste buds. Two par­al­lel rows of gill slits are found pos­te­rior to the mouth. The col­oration dis­plays the coun­ter­shad­ing pat­tern is typ­i­cal of many aquatic an­i­mals. The dor­sum is darkly col­ored, pre­vent­ing preda­tors swim­ming above them from see­ing them against the sand, while the lighter col­ored belly ob­scures an in­di­vid­u­als body out­line from preda­tors below, due to in­com­ing sun­light. (Fyler and Caira, 2006; Lund­berg, et al., 2000; Vidthayanon, et al., 2011)

• Other Physical Features
• ectothermic
• bilateral symmetry
• venomous

• Sexual Dimorphism
• sexes alike

• Range mass

  600 (high) kg

  1321.59 (high) lb

• Range length

  300 (high) cm

  118.11 (high) in

De­vel­op­ment

Lit­tle is known about the de­vel­op­ment of giant fresh­wa­ter stingrays. How­ever, it is likely sim­i­lar to that of a re­lated species, Dasy­atis sabina (At­lantic stingray). In At­lantic stingrays, de­vel­op­ment takes ap­prox­i­mately 12 weeks. For the first 4 to 6 weeks, the em­bryo elon­gates but there is no head or body de­vel­op­ment. After 6 weeks, gills begin to grow and the fins and eyes begin to de­velop. The tail and spine ap­pear shortly be­fore hatch­ing and at birth, stingrays look like minia­ture adults. The av­er­age disc width of newly hatched young is 30 cm. (John­son and Snel­son, 1996; Luna and Wi­ethuchter, 2011)

• Development - Life Cycle
• indeterminate growth

Re­pro­duc­tion

Fe­male stingrays ap­pear to choose mates by using their elec­trosen­sory sys­tem to de­tect sex-spe­cific elec­tri­cal sig­nals pro­duced by males. Once a fe­male has mated, they leave the male and re­side with other fe­males in brack­ish wa­ters until they give birth. Males have a clasper (a cop­u­la­tory struc­ture that holds sperm) at­tached to each pelvic fin. Hav­ing mul­ti­ple claspers al­lows a male stingray to im­preg­nate a fe­male with one clasper and then seek out an­other fe­male to im­preg­nate with the re­main­ing clasper. Male stingrays pro­duce and store sperm through­out the year to en­sure that they have suf­fi­cient sperm for use dur­ing the mat­ing sea­son. (John­son and Snel­son, 1996)

• Mating System
• polygynous

Very lit­tle is known re­gard­ing the re­pro­duc­tive cycle of giant fresh­wa­ter stingrays in the wild. Cap­tive breed­ing ef­forts have in­di­cated that preg­nant fe­males give birth to 1 to 2 off­spring per breed­ing event. How­ever, other in­for­ma­tion from cap­tive breed­ing pro­grams is sparse and most of these pro­grams have been dis­con­tin­ued. (Fowler, et al., 2005)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • internal
• ovoviviparous

• Breeding interval

  Frequency of breeding in giant freshwater stingrays is currently unknown

• Breeding season

  The seasons in which fertilization and birth occur are currently unknown

• Range number of offspring

  1 to 2

Male stingrays pro­vide no parental in­vest­ment to their off­spring after mat­ing. Fe­males give birth to live young in es­tu­ar­ine birthing grounds. They then take care of their newly hatched young until they are roughly one-third the size of the fe­male, at which point they are con­sid­ered ma­ture and will move to com­pletely fresh­wa­ter habi­tats. (John­son and Snel­son, 1996)

• Parental Investment
• female parental care
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female

Lifes­pan/Longevity

There is lit­tle in­for­ma­tion re­gard­ing the lifes­pan of this species. How­ever, other mem­bers of the genus Hi­man­tura have been re­ported to live 5 to 10 years in the wild. This species fares poorly in cap­tiv­ity, due to the dif­fi­cul­ties as­so­ci­ated with pro­vid­ing proper food and space. (Com­pagno and Cook, 1995; Last and Stevens, 2009; Vidthayanon, et al., 2011)

Be­hav­ior

Giant fresh­wa­ter stingrays are so­cial, seden­tary an­i­mals that gen­er­ally stay in one area and within a par­tic­u­lar group. They are likely able to com­mu­ni­cate with con­specifics via elec­tri­cal im­pulses sent through the body, as has been found in other stingray species. There have been at­tempts to ex­am­ine the range and move­ment using tag­ging stud­ies, but no suc­cess­ful re­sults were col­lected from this ex­per­i­ment. (Vidthayanon, et al., 2011)

• Key Behaviors
• natatorial
• nocturnal
• motile
• sedentary
• social

Home Range

Giant fresh­wa­ter stingrays gen­er­ally stay in the same river sys­tem in which they were hatched, but the av­er­age size of an in­di­vid­ual's day to day range is cur­rently un­known. (John­son and Snel­son, 1996)

Com­mu­ni­ca­tion and Per­cep­tion

In­traspe­cific com­mu­ni­ca­tion has not yet been stud­ied in this species, but sim­i­lar species of stingrays have been doc­u­mented to com­mu­ni­cate by gen­er­at­ing and sens­ing species- and con­text-spe­cific elec­tri­cal im­pulses. Stingrays have an ex­ten­sive elec­trosen­sory sys­tem that in­cludes many re­cep­tive or­gans known as Am­pul­lae of Loren­zini. There are pores all over the stingray’s body lead­ing to canals under the skin. Each pore is full of many sen­sory re­cep­tor cells. The arrange­ment of the pores al­lows the stingray to de­tect move­ment of prey and preda­tors via the elec­tri­cal fields that these move­ments gen­er­ate. Stingrays can also per­ceive their en­vi­ron­ment vi­su­ally, al­though this species does not rely on this sense as much be­cause they are found in areas that are dark and full of sed­i­ment. Like other stingray species, giant fresh­wa­ter stingrays also have well-de­vel­oped senses of smell and hear­ing, as well as a lat­eral line sys­tem for de­tect­ing vi­bra­tions in the water (Hart, et al., 2011; Sis­neros and Tri­cas, 2002)

• Communication Channels
• visual
• electric

• Perception Channels
• visual
• tactile
• acoustic
• vibrations
• chemical
• electric

Food Habits

Giant fresh­wa­ter stingrays gen­er­ally feed on river bot­toms. Their mouth con­tains two jaws that act like crush­ing plates, and small teeth to con­tinue chew­ing up food. Their diet con­sists mainly of ben­thic fishes and in­ver­te­brates. (Luna and Wi­ethuchter, 2011; Vidthayanon, et al., 2011)

• Primary Diet
• carnivore
  • piscivore
  • eats non-insect arthropods
  • molluscivore
  • vermivore

• Animal Foods
• fish
• mollusks
• aquatic or marine worms
• aquatic crustaceans

Pre­da­tion

Adult giant fresh­wa­ter stingrays, as the largest or­gan­isms in their habi­tats, have few nat­ural preda­tors. Their coun­ter­shaded color pat­tern and seden­tary lifestyle offer even small in­di­vid­u­als pro­tec­tion from larger preda­tors, as they are able to blend in with the river bot­tom. When swim­ming above the bot­tom, their light-col­ored un­der­side al­lows them to be hid­den from preda­tors, due to the sun­light from above. This species also has a strong, ser­rated, ven­omous spine on its tail, which can be used in self de­fense. The only major preda­tor of giant fresh­wa­ter stingrays is hu­mans. In Thai­land, fish­er­men seek out these an­i­mals for food, per­sonal aquar­i­ums, and sport. (Vidthayanon, et al., 2011)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • humans (Homo sapiens)

Ecosys­tem Roles

Giant fresh­wa­ter stingrays act as preda­tors of smaller an­i­mals liv­ing on or in the river floor. A large num­ber of ces­tode species (tape­worms) have been de­scribed from the in­tes­tine of this species, which is thought to be their only host. The mode of trans­mis­sion for these tape­worms is cur­rently un­known. (Fyler and Caira, 2006; Healy, 2006)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Giant fresh­wa­ter stingrays are a food source in some Asian cities, even though it is now il­le­gal to fish for this en­dan­gered species. They are also col­lected for aquar­i­ums and are a pop­u­lar sport fish. (Com­pagno and Cook, 1995; Rain­both, 1996; Vidthayanon, et al., 2011)

• Positive Impacts
• food
• ecotourism

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

When fish­er­men try to catch giant fresh­wa­ter stingrays, they will whip their tail (bear­ing its large, ser­rated, ven­omous spine) to try and get away. These spines have been re­ported to be strong enough to go through wooden boats. There have been no re­ports of un­pro­voked at­tacks. (Monkol­pr­a­sit and Roberts, 1990)

• Negative Impacts
• injures humans
  • bites or stings
  • venomous

Con­ser­va­tion Sta­tus

Due to rapidly de­clin­ing num­bers of giant fresh­wa­ter stingrays, the IUCN Red List has de­clared this species to be en­dan­gered. In Thai­land, cap­tive breed­ing ef­forts are un­der­way to re­build the pop­u­la­tion, though rates of sur­vival in cap­tiv­ity are very low. Sci­en­tists are work­ing to tag the re­main­ing stingrays in order to un­der­stand their move­ment pat­terns and im­prove con­ser­va­tion ef­forts, but suf­fi­cient re­sults are still lack­ing. (Vidthayanon, et al., 2011)

• IUCN Red List

  Endangered

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Con­trib­u­tors

Kelsey Thomp­son (au­thor), Rad­ford Uni­ver­sity, Karen Pow­ers (ed­i­tor), Rad­ford Uni­ver­sity, Kier­sten Newtoff (ed­i­tor), Rad­ford Uni­ver­sity, Melissa Whistle­man (ed­i­tor), Rad­ford Uni­ver­sity, Je­remy Wright (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

Mur­doch Uni­ver­sity. Sta­tus of fresh­wa­ter and es­tu­ar­ine Elas­mo­branchs in North­ern Aus­tralia. 0642553378. Aus­tralia: Nat­ural Her­itage Trust. 2003. Ac­cessed Feb­ru­ary 05, 2012 at http://​www.​environment.​gov.​au/​coasts/​publications/​pubs/​elasmo-north.​pdf.

Com­pagno, L., S. Cook. 1995. "Sta­tus of the giant fresh­wa­ter stingray (whipray) Hi­man­tura chaophraya (Monkol­pr­a­sit and Roberts 1990)" (On-line). Ac­cessed Feb­ru­ary 05, 2012 at http://​www.​flmnh.​ufl.​edu/​fish/​organizations/​ssg/​sharknews/​sn5/​shark5news7.​htm.

Fowler, S., R. Ca­vanagh, M. Camhi, G. Burgess, G. Cail­liet, S. Ford­ham, C. Simpfendor­fer, J. Mu­sick. 2005. Sharks, Rays and Chi­maeras: The Sta­tus of the Chon­drichthyan Fishes. Sta­tus Sur­vey. Gland, Switzer­land and Cam­bridge, UK: IUCN/SSC Shark Spe­cial­ist Group.

Fyler, C., J. Caira. 2006. Five new species of Acan­thoboth­rium (Tet­ra­phyl­lidea: On­choboth­ri­idae) from the fresh­wa­ter stingray Hi­man­tura chaophraya (Ba­toidea: Dasy­ati­dae) in Malaysian Bor­neo. The Jour­nal of Par­a­sitol­ogy, 92/1: 105-125.

Hart, N., T. Lin­sey, S. Collin. 2011. Vi­sual com­mu­ni­ca­tion in Elas­mo­brachs. Com­mu­ni­ca­tion in Fishes, 13:1: 337-383.

Healy, C. 2006. Three new species of Rhineboth­rium (Ces­toda: Tet­ra­phyl­lidea) from the fresh­wa­ter whipray, Hi­man­tura chaophraya, in Malaysian Bor­neo. The Jour­nal of Par­a­sitol­ogy, 92/2: 364-374.

John­son, M., F. Snel­son. 1996. Re­pro­duc­tive life his­tory of the At­lantic stingray, Dasy­atis sabina (pisces, Dasy­ati­dae), in the fresh­wa­ter St. Johns River, Florida. Bul­letin of Ma­rine Sci­ence, 59/1: 74-88.

Last, P., B. Man­jaji-Mat­sumoto. 2008. Hi­man­tura da­lyen­sis sp. nov., a new es­turine whipray (Mylio­ba­toidei: Dat­sy­ati­dae) from north­ern Aus­tralia. Pp. 283-291 in P Last, W White, J Pogonoski, eds. De­scrip­tions of new Aus­tralian Chon­drichthyans, Vol. CSIRO Ma­rine and At­mos­pheric Re­search Paper No. 022. Ho­bart, Tas­ma­nia: CSIRO Ma­rine and At­mos­pheric Re­search.

Last, P., J. Stevens. 2009. Sharks and Rays of Aus­tralia. Aus­tralia: CSIRO.

Luna, S., A. Wi­ethuchter. 2011. "Hi­man­tura chaophraya Monkol­pr­a­sit & Roberts, 1990 fresh­wa­ter whipray" (On-line). Ac­cessed Feb­ru­ary 05, 2012 at http://​www.​fishbase.​org/​summary/​Himantura-chaophraya.​html.

Lund­berg, J., M. Kot­te­lat, G. Smith, M. Sti­assny, A. Gill. 2000. So many fishes, so lit­tle time: An overview of re­cent ichty­olog­i­cal dis­cov­ery in con­ti­nen­tal wa­ters. Mis­souri Botan­i­cal Gar­den, 87/1: 26-62.

Marzullo, T., B. Wueringer, L. Jnr, S. Collin. 2011. De­scrip­tion of the mechanore­cep­tive lat­eral line and elec­trore­cep­tive am­pullary sys­tems in the fresh­wa­ter whipray, Hi­man­tura da­lyen­sis. Ma­rine and fresh­wa­ter re­search, 62/6: 771-779.

Monkol­pr­a­sit, S., T. Roberts. 1990. Hi­man­tura chaophraya, a new giant fresh­wa­ter stingray from Thai­land. Japan­ese Jour­nal of Ichthy­ol­ogy, 37/3: 203-208.

Rain­both, W. 1996. Fishes of the Cam­bo­dian Mekong. Rome, Italy: FAO.

Sis­neros, J., T. Tri­cas. 2002. Neu­roethol­ogy and life his­tory adap­ta­tions of the elas­mo­branch elec­tric sense. Jour­nal of Phys­i­ol­ogy-Paris, 96/5-6: 379-389.

Vidthayanon, C., I. Baird, Z. Hogan. 2011. "Hi­man­tura chaophraya" (On-line). Ac­cessed Feb­ru­ary 05, 2012 at http://​www.​iucnredlist.​org/​apps/​redlist/​details/​195320/​0.