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dc.contributor.authorSugasawa, Shoko
dc.contributor.authorKlump, Barbara Christina
dc.contributor.authorSt Clair, James J. H.
dc.contributor.authorRutz, Christian
dc.date.accessioned2018-12-07T00:36:26Z
dc.date.available2018-12-07T00:36:26Z
dc.date.issued2017-12-18
dc.identifier.citationSugasawa , S , Klump , B C , St Clair , J J H & Rutz , C 2017 , ' Causes and consequences of tool shape variation in New Caledonian crows ' , Current Biology , vol. 27 , no. 24 , e4 , pp. 3885-3890 . https://doi.org/10.1016/j.cub.2017.11.028en
dc.identifier.issn0960-9822
dc.identifier.otherPURE: 251739227
dc.identifier.otherPURE UUID: d3cebed9-0147-4036-af90-1f7629b388e9
dc.identifier.otherScopus: 85039933824
dc.identifier.otherORCID: /0000-0003-4452-1177/work/58531620
dc.identifier.otherORCID: /0000-0001-5187-7417/work/60427555
dc.identifier.otherWOS: 000418285000033
dc.identifier.urihttps://hdl.handle.net/10023/16640
dc.descriptionThis study was funded through a BBSRC David Phillips Fellowship (BB/G023913/2; C.R.), studentships from JASSO (S.S.; L12126010025) and BBSRC/University of St Andrews (B.C.K.), and a JSPS overseas research fellowship (S.S.; H28/1018).en
dc.description.abstractHominins have been making tools for over three million years [1], yet the earliest known hooked tools appeared as recently as 90,000 years ago [2]. Hook innovation is likely to have boosted our ancestors’ hunting and fishing efficiency [3], marking a major transition in human technological evolution. The New Caledonian crow is the only non-human animal known to craft hooks in the wild [4 ; 5]. Crows manufacture hooked stick tools in a multi-stage process, involving the detachment of a branch from suitable vegetation; “sculpting” of a terminal hook from the nodal joint; and often additional adjustments, such as length trimming, shaft bending, and bark stripping [4; 6 ; 7]. Although tools made by a given population share key design features [4; 6 ; 8], they vary appreciably in overall shape and hook dimensions. Using wild-caught, temporarily captive crows, we experimentally investigated causes and consequences of variation in hook-tool morphology. We found that bird age, manufacture method, and raw-material properties influenced tool morphology, and that hook geometry in turn affected crows’ foraging efficiency. Specifically, hook depth varied with both detachment technique and plant rigidity, and deeper hooks enabled faster prey extraction in the provided tasks. Older crows manufactured tools of distinctive shape, with pronounced shaft curvature and hooks of intermediate depth. Future work should explore the interactive effects of extrinsic and intrinsic factors on tool production and deployment. Our study provides a quantitative assessment of the drivers and functional significance of tool shape variation in a non-human animal, affording valuable comparative insights into early hominin tool crafting [9].
dc.language.isoeng
dc.relation.ispartofCurrent Biologyen
dc.rights© 2017 Elsevier Ltd. This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1016/j.cub.2017.11.028en
dc.subjectAcheuleanen
dc.subjectArtifacten
dc.subjectChimpanzeeen
dc.subjectConstruction behavioren
dc.subjectCumulative cultureen
dc.subjectExtractive foragingen
dc.subjectHooken
dc.subjectNew Caledonian crowen
dc.subjectTool manufactureen
dc.subjectTool useen
dc.subjectQH301 Biologyen
dc.subjectQL Zoologyen
dc.subjectBF Psychologyen
dc.subjectNDASen
dc.subjectBDCen
dc.subjectR2Cen
dc.subject.lccQH301en
dc.subject.lccQLen
dc.subject.lccBFen
dc.titleCauses and consequences of tool shape variation in New Caledonian crowsen
dc.typeJournal articleen
dc.contributor.sponsorBBSRCen
dc.description.versionPostprinten
dc.contributor.institutionUniversity of St Andrews. School of Biologyen
dc.contributor.institutionUniversity of St Andrews. Centre for Social Learning & Cognitive Evolutionen
dc.contributor.institutionUniversity of St Andrews. Centre for Biological Diversityen
dc.identifier.doihttps://doi.org/10.1016/j.cub.2017.11.028
dc.description.statusPeer revieweden
dc.date.embargoedUntil2018-12-07
dc.identifier.grantnumberBB/G023913/2en


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