Parallel tool industries in New Caledonian crows.
Individual specialization in the use of foraging tools occurs in hunter-gatherer societies but is absent in non-human primate tool use. 'Parallel tool industries' in hunter-gatherers are mainly based on strict sexual division of labour that is highly reliant on social conformity. Here, we show that 12 individuals in a population of New Caledonian crows on Maré Island had strong preferences for either stick tools or pandanus tools. Eight of the 12 crows had exclusive preferences. The individual specialization that we found is probably associated with different foraging niches. However, in spite of sexual size dimorphism there was no significant association between the sex of crows and their tool preferences. Our findings demonstrate that highly organized, strict sexual division of labour is not a necessary prerequisite for the evolution of parallel tool industries.
Hunt
Gavin R
GR
Department of Psychology, University of Auckland, Private Bag 92019 Auckland, New Zealand. grhunt10@hotmail.com
Gray
Russell D
RD
D000818:Animals; D016009:Chi-Square Distribution; D046368:Crows / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D008297:Male; D009510:New Caledonia; D018515:Plant Leaves; D018547:Plant Stems; D012737:Sex Factors; D053001:Tool Use Behavior / Q000502:physiology*