In this study, we tested 8 Sleepy-lizards (Tiliqua rugosa asper) on their ability to spontaneously choose the larger of two quantities based on continuous or discrete information. We recorded the lizards' identity, weight (g) and snout-vent length (mm). As we tested lizards in two batches (groups), we also recorded if they belonged to group A or B. In regards to the experiment, we recorded session (day), trial (1-12), stage (preference test or quantity discrimination), date of the test day and start time of the first trial, the test (continuous or discrete) and the comparison. We measured lizards' choice behaviour by recording the choice of the quantity as well as a binary version that represented the choice of the larger quantity as 1 and the smaller choice as 0. Finally, we also quantified the time it took lizards to make a choice from trial videos in seconds (latency). NA values indicate either no data or no choice. We analysed the choice behaviour using the binary choice data and also the latency to understand if lizards were able to discriminate quantities and if they showed a speed-accuracy trade-off. We provide trial-by-trial raw data in a horizontal format. How to transpose the data set into a vertical format and details regarding further calculations and statistical analyses can be found on OSF, doi: 10.17605/OSF.IO/PR46D

Data were collected in a Y-maze and the first choice of each individual recorded. Additionally, we also recorded the latency to choice from videos.