Serial reversal learning in freshwater stingrays (Potamotrygon motoro)

Visual discrimination and resolution in freshwater stingrays (Potamotrygon motoro)

“…It is necessary to note that the results of each trial cannot be seen as independent from other trials Fig. 2 Holding tank (2.30 m × 2.07 m × 0.40 m) with (1) filter system, (2) aquarium heaters, (3) air stones, and (4) pumps and incorporating the experimental apparatus: (a) guillotine door 1, (b) starting box, (c) guillotine door 2, (d) decision area, (e) clear barrier, (f) decision line, (g) stimulus wall (adapted from Daniel and Schluessel 2020) within a session, and experience from prior trials in any session can inform an animal's subsequent decisions.…”

“…It has been shown that Potamotrygon motoro uses vision to orient spatially (Schluessel and Bleckmann 2005;Schluessel et al 2015;Schluessel and Ober 2018), and the species has been successfully trained in cognitive behavioral studies using visual stimuli (e.g. Seifert 2017, Daniel and Schluessel 2020). In the field, juveniles have furthermore been documented preying on snails above water level during the day (Garrone- Neto and Sazima 2009), a behavior which likely requires visual perception.…”

“…Successful discrimination implied that stimuli were perceived as consisting of multiple separate entities, but it remained ambiguous whether this perception was based on elements of form or contrast. In a serial reversal learning experiment, Daniel and Schluessel (2020) used stimuli that differed in orientation, brightness, and color, but it was not tested which of these properties the stingrays used for discrimination. The present study thus sought to clarify and elaborate on previous experiments with this species while providing leads for further research.…”

Counting on Numbers—Numerical Abilities in Grey Bamboo Sharks and Ocellate River Stingrays

“…Several elasmobranch species, including the grey bamboo shark ( Chiloscyllium griseum ) and the ocellate river stingray ( Potamotrygon motoro ), have been part of a range of cognition experiments and have shown various visual discrimination as well as orientation abilities (see reviews [ 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ]). Adding to that, freshwater stingrays ( Potamotrygon castexi ) are able to use water as a tool to extract food from a tube [ 54 ].…”

“…They also performed well in a range of optical illusion experiments [ 50 , 58 ]. In recent studies a wide range of visual discrimination abilities were shown in P. motoro , including first evidence for memory retention [ 45 ], serial reversal learning [ 46 ] and colour discrimination [ 45 ]. In addition, C. griseum and P. motoro both seem to be able to use spatial maps to orientate, can use different orientation strategies and memorize spatial tasks over a period of several weeks or months [ 51 , 59 ].…”