New Caledonian crows have, in the past, distinguished themselves with their advanced tool using abilities. A team of researchers from the University of Auckland and the University of Cambridge have now shown these crows can learn to use new types of tools.
When confronted with the Aesop's fable paradigm, which requires stones to be dropped into a water-filled tube to bring floating food within reach, the crows quickly learned to use stones as tools.
They then preferred to drop into the tube large rocks rather than small rocks, and heavy objects over light objects (which floated on the surface of the water and so were ineffective).
Further experiments showed that the crows' performances were not based on simple learning, which suggests that the crows had some understanding of how the task actually worked. The authors, therefore, concluded that these crows have cognitive mechanisms beyond simple associative learning that are capable of processing causal information about novel tool types.
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Taylor AH, Elliffe DM, Hunt GR, Emery NJ, Clayton NS, et al. (2011) New Caledonian Crows Learn the Functional Properties of Novel Tool Types. PLoS ONE 6(12): e26887. doi:10.1371/journal.pone.0026887