Four ocellate river stingray joined the collection in August 2011 in the Worlds Apart exhibit! The stingray have been named Little Sun, Ringo, Lucky and Dot by their keepers and can be seen hiding amongst the sand at the bottom of the pool, or gliding along the bed by their characteristic oscillated movement.
The stingray have joined the pacu fish within the main pool in the inside small primate walkthrough and can be distinguished by their decorative spotted markings with a greyish-brown upper surface patterned with distinct yellow-orange spots, and a white underside. The species also have a single spine borne at the tip of the tail, which is capable of delivering a painful sting.
The four stingray are juveniles and so are still a smaller size, their body resembles that of an oval disc, and once grown can reach up to 100cm in width. Sexual maturity is not reached until around three years of age, when the stingray measures between 30 and 35 centimetres across.
A South American species, the ocellate river stingray has a wide distribution range, extending across Argentina, Brazil, Paraguay, Uruguay and Venezuela. While most rays are marine, this species is one of the few that is restricted to freshwater.
The species is listed as data deficient on the IUCN Red List, due to lack of life history and population data available for this species. Further study for the future has been highly recommended, as the species faces threats from adults being fished for food and younger rays collected for the ornamental fish trade. Habitat degredation within the distribution range is also an issue, for example, the damming of the Río Paraná system for construction of navigation and hydroelectric plants and ports along the river cause a strong threat to the species survival.