Betty the crow is right-handed

6 April 2004

New Caledonian crows, known to be very proficient tool-users, have a preferred way of holding their tools comparable to the way humans are either right- or left-handed, according to research by Oxford zoologists, recently published in 'Biology Letters'.

Studying the tool use of 10 captive New Caledonian crows, the researchers found that each bird had a consistent preference for holding a piece of dowelling either near its left or its right cheek when trying to retrieve mealworms from a hole in a piece of wood. Five of the birds preferred to use tools left-laterally, and five right but laterality did not obviously differ between male and female crows.

The findings are surprising as it is rare to find animals with such exclusive lateral preferences for manipulative tasks. Only 50 per cent of chimpanzees, for example, are committed to always using the same hand for tool use.

Mr Alex Weir of the Behavioural Ecology Research Group at the Oxford University's Department of Zoology said: 'Our results show that individuals have very strongly preferred ways to hold tools but there is no apparent population preference. This result is still preliminary, since the sample size is too small to firmly conclude that there is not population-level laterality.

'However these results appear to contrast with other research, which showed that crows have a population-level bias for manufacturing tools, suggesting that the manufacturing and use of tools in this species may have different neural underpinnings.'

For more information please contact the Press Office on 01865 280528. Pictures or short film clips are available on request.

Notes to editors:

• One of the birds, called Betty, gained fame in 2002, when she took part in an experiment by the same group which showed that crows had some understanding of physics as they were able to manufacture hooks to retrieve food from a vertical tube.
• The research was published in: Lateralization of tool use in New Caledonian crows (Corvus moneduloides) by Mr AAS Weir, Mr B Kenward, Dr J Chappell and Professor A Kacelnik, 2004, Proceedings of the Royal Society of London B (Suppl.), 'Biology Letters'. DOI 10.1098/rsbl.2004.0183
• For more information about the research including a movie see http://users.ox.ac.uk/~kgroup/tools/laterality.html. The site also contains links to the 2002 research about tool manufacturing by Caledonian crows.