White-Blotched River Stingray/Xingu River Ray/Polka-Dot Stingray

ANIMAL:
White-Blotched River Stingray/Xingu River Ray/Polka Dot Stingray Potamotrygon leopoldi

Type of Animal:
Ray

Habitat:
Rivers, river bottoms, sand banks, slow-moving tributaries w/ sand/mud substrate, river shallows, flooded forest, terrestrial lakes/ponds formed by receding flood waters

Location(s):
Xingu, Fresco, Curua, & Iriri rivers of N Brazil

Appearance:
Black w/ white blotchy polka-dot like spots, brownish-dusky belly, looks like floating disc

Food/Diet:
Fish, crustaceans, worms, snails, clams, mussels, aquatic insect larvae

Status in Wild:
Stable

Conservation:
Breeding in aquariums, marine parks, & zoos

Lifestyle:
Solitary or small groups of 2-8 rays. Juveniles found in groups of 7-20 rays.

Additional Info:
 
Called:
Male
Female
Young: Pup
Group: School/Fever
 
Weight:
Male: 40 lbs
Female: 44 lbs
 
Gestation:
3-12 months 

Life Span:
5-15 years

Width:
Male: 1.47 ft
Female: 2.13 ft
Young: 9 in

Body Length:
Male: 2.46 ft
Female: 3.28 ft

Tail Length:
Male: 3 ft
Female: 4 ft

They’re ovoviviparous, meaning young nourished by egg yolks in mom’s body, coming out as live young. Females give birth to 4-12 pups.
 
They’re ambush predators.
 
While stable, potential threats are water pollution, habitat loss/degradation, collection for aquarium/pet trade, dam construction, killing out of fear, overfishing, agriculture, mining, & logging.
 
Like other freshwater stingrays, they have great eyesight.
 
Ampullae of Lorenzini located on skin around nose/mouth allow them to detect minute electric fields generated by other living things. Sensory detection notifies them of possible prey nearby.
 
Usually hunt at night.
 
Males have claspers used to internally fertilize females.
 
Sexually mature at 10 months old.
 
Males bite edges of female disc to encourage them to accept. Then male bites/hold on to female while maneuvering himself to impregnate a uterus w/ single clasper, belly to belly. Mating itself lasts less than half a minute.

Fun Fact(s):
Scientific name means Leopold’s River Stingray, which is another name for this species. Other names-Black Diamond Stingray, Black Devil Stingray, Black Ray, Yellow-Spotted Black Amazon Stingray, & Eclipse Ray.
 
No 2 stingrays have same spot pattern.
 
Known to be fast learners.
 
While docile, these animals & close relatives inflict more human injuries yearly than any other animals in Amazonian rivers, most likely because they bury themselves in sand/mud & inadvertently get stepped on. Often more feared than piranhas due to powerful painful sting. Younger animals have more toxic venom than older animals. Freshwater stingray venom more potent than those of saltwater stingrays due to having more venom secreting cells along barbs.
 
If cut/lost in flesh of threat, barbs can grow back within a few months.

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