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Quantitative abilities in a reptile (Podarcis sicula)
Maria Elena Miletto Petrazzini1, Isabel Fraccaroli2, Francesco Gariboldi2
1Department of General Psychology, University of Padova, Padova, Italy mariaelena.milettopetrazzini@gmail.com.
Biology Letters
|April 14, 2017
Summary
Ruin lizards can identify larger individual food items but struggle to select the greater quantity when presented with multiple food options. This suggests unique quantitative abilities in reptiles compared to other vertebrates.
Area of Science:
- Comparative cognition
- Animal behavior
- Herpetology
Background:
- Optimizing foraging behavior relies on identifying the most abundant prey.
- This cognitive skill is documented across vertebrates, excluding reptiles.
- Reptiles' numerical cognition remains largely unexplored.
Purpose of the Study:
- To investigate the spontaneous ability of ruin lizards (Podarcis siculus) to choose larger quantities of food.
- To determine if lizards can discriminate between single larger food items and larger groups of food items.
Main Methods:
- Experiment 1: Lizards chose between two single food items of varying sizes (0.25, 0.50, 0.67, 0.75 ratios).
- Experiment 2: Lizards chose between two groups of food items with differing quantities (1 vs. 4, 2 vs. 4, 2 vs. 3, 3 vs. 4 items).
Main Results:
- Lizards successfully selected the larger single food item in Experiment 1.
- Lizards failed to select the larger group of food items in Experiment 2 across all contrasts.
- This indicates a difference in quantity discrimination based on item numerosity.
Conclusions:
- Ruin lizards demonstrate an ability to assess the size of individual food items.
- Lizards do not appear to discriminate between larger quantities when presented with multiple food items.
- These findings raise questions about the distinct nature of quantitative abilities in reptiles.