Numerical discrimination by frogs (Bombina orientalis).

Area of Science:

• Comparative psychology
• Animal behavior
• Sensory processing

Background:

• Quantity discrimination is documented in mammals and birds, but less so in amphibians.
• For amphibians, it's unclear if quantity discrimination relies on number or physical variables.
• Investigating numerical cognition in amphibians like frogs is crucial for understanding the evolution of number sense.

Purpose of the Study:

• To investigate quantity discrimination in frogs (Bombina orientalis).
• To determine if frogs distinguish prey quantity based on number or continuous physical variables.
• To explore potential differences in processing small versus large quantities.

Main Methods:

• Free-choice experiments were conducted with Bombina orientalis.
• Frogs were presented with varying amounts of Tenebrio molitor larvae.
• Systematic controls were implemented for prey surface area, volume, weight, and movement.

Main Results:

• Frogs demonstrated quantity discrimination for small numerousness (1 vs. 2, 2 vs. 3) and large numerousness (3 vs. 6, 4 vs. 8).
• Clear evidence suggests numerical discrimination in small quantities (1 vs. 2) even when physical variables were controlled.
• For large quantities, dominance of number versus surface area remained ambiguous.

Conclusions:

• Frogs exhibit quantity discrimination abilities, suggesting a capacity for numerical processing.
• Task demands likely influence distinct processing systems for small and large numerousness.
• The susceptibility to continuous variables varies between small and large quantity discrimination tasks.