Tool-use by rats (Rattus norvegicus): tool-choice based on tool features
In the present study, we investigated whether rats (Rattus norvegicus) could be trained to use tools in an experimental setting. In Experiment 1, we investigated whether rats became able to choose appropriate hook-shaped tools to obtain food based on the spatial arrangements of the tool and food, similar to tests conducted in non-human primates and birds. With training, the rats were able to choose the appropriate hooks. In Experiments 2 and 3, we conducted transfer tests with novel tools. The rats had to choose between a functional and non-functional rake-shaped tool in these experiments. In Experiment 2, the tools differed from those of Experiment 1 in terms of shape, color, and texture. In Experiment 3, there was a contradiction between the appearance and the functionality of these tools. The rats could obtain the food with a functional rake with a transparent blade but could not obtain food with a non-functional rake with an opaque soft blade. All rats chose the functional over the non-functional rakes in Experiment 2, but none of the rats chose the functional rake in Experiment 3. Thus, the rats were able to choose the functional rakes only when there was no contradiction between the appearance and functionality of the tools. These results suggest that rats understand the spatial and physical relationships between the tool, food, and self when there was no such contradiction.
KeywordsTool-use behavior Tool-choice behavior Rodents Rats
No external funding supported this research.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
The datasets obtained during the current study are available from the corresponding author on reasonable request.
Research involving animals
All applicable institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted.
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