Laterality in tool manufacture by crows

  • An Erratum to this article was published on 07 February 2002

Neural processing and not ecological factors may influence 'handedness' in these birds.


New Caledonian crows (Fig. 1) fashion tapered tools from either the left or the right edge of the long narrow leaves of pandanus trees or screw pines1,2, which they use to extract invertebrates in rainforest vegetation2. Although right-handedness is thought to be uniquely human3, we show here that crows from different localities display a widespread laterality in making their tools, indicating that this behaviour is unlikely to be attributable to local social traditions or ecological factors. To our knowledge, this is the first demonstration of species-level laterality in manipulatory skills outside humans.

These birds make tools to probe for insects, including the 'crochet' tool illustrated.

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Figure 2: Lateralization in the manufacture of stepped tools from Pandanus sp. leaves by New Caledonian crows.


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Correspondence to Gavin R. Hunt.

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