Why do vultures have bald heads? The role of postural adjustment and bare skin areas in thermoregulation

Ward, J., McCafferty, D. , Houston, D. and Ruxton, G.D. (2008) Why do vultures have bald heads? The role of postural adjustment and bare skin areas in thermoregulation. Journal of Thermal Biology, 33(3), pp. 168-173. (doi: 10.1016/j.jtherbio.2008.01.002)

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Abstract

Griffon vultures (Genus Gyps) have large areas of bare skin on their body, and by changing their posture they can vary the extent to which these are covered by feathers. We used a mathematical model to estimate the amount of bare skin exposed in the postures adopted in cold and hot conditions. Measurements of heat flow through different parts of museum skins, which differed in their feather density, were then used together with the estimates of proportions of body surface covered by each feather density type, to determine rates of heat loss from the whole body. Postural change can cause the proportion of body surface composed of bare skin areas to change from 32% to 7%, and in cold conditions these changes are sufficient to account for a 52% saving in heat loss from the body. We suggest that the bare skin areas in griffon vultures may play an important role in thermoregulation.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McCafferty, Dr Dominic and Ruxton, Professor Graeme and Houston, Professor David
Authors: Ward, J., McCafferty, D., Houston, D., and Ruxton, G.D.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
College of Social Sciences > School of Education
College of Medical Veterinary and Life Sciences > School of Life Sciences
Journal Name:Journal of Thermal Biology
Publisher:Pergamon Press (Elsevier Science)
ISSN:0306-4565
ISSN (Online):1879-0992

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