White Wolves Can Stand the Heat

Abstract

T. M. Anderson et al. report that wolves of the northwestern forest in North America are dark in comparison to the wolves of the tundra (“Molecular and evolutionary history of melanism in North American gray wolves,” Reports, 6 March, p. [1339][1]). Anderson et al. suggest in passing that the dark coats might better hide preying wolves in the forest. An alternative adaptive explanation is that in the summer, a black tundra wolf could overheat. A study by Finch and Western provides evidence of the temperature-related consequences of coat color among pastoralists' cattle in Kenya ([ 1 ][2]). Finch and Western showed experimentally that black Boran Zebu cattle in the sun became hotter than did white cattle and that across Kenya, as heat stress increased, the proportion of dark cattle in herds decreased. They also found that herders report more dark than light cattle dying during droughts at low altitude. Finch and Western related the variation in color to the social system of the Kenyan herders. Some of them divide themselves into clans according to the preferred color of their cattle, and the preference correlates adaptively with the usual heat stress of the clans' home ranges. 1. [↵][3] 1. V. A. Finch, 2. D. Western , Ecology 58, 1384 (1977). [OpenUrl][4][CrossRef][5][Web of Science][6] [1]: /lookup/doi/10.1126/science.1165448 [2]: #ref-1 [3]: #xref-ref-1-1 View reference 1 in text [4]: {openurl}?query=rft_id%253Dinfo%253Adoi%252F10.2307%252F1935090%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [5]: /lookup/external-ref?access_num=10.2307/1935090&link_type=DOI [6]: /lookup/external-ref?access_num=A1977ES71000015&link_type=ISI