Kuyenda Bushcamp’s Phil Berry has teamed up with Professor Fred Bercovitch to analyze data on giraffe coat colour that Phil has been collecting over his many years in the South Luangwa. The paper, entitled Darkening coat colour reveals life history and life expectancy of male Thornicroft’s giraffes, has been published in Journal of Zoology in March 2012.
As reported last year, the two giraffe experts spent a month together at Kuyenda Bushcamp & Mfuwe Lodge working on a number of scientific papers about the Thornicroft’s giraffe, a unique subspecies of the Luangwa Valley. The article can be downloaded from the Journal of Zoology website, and below is an overveiw of their findings.
Much of the information available about the life history of the giraffe, Giraffa camelopardalis, is derived from captive studies or short-term ﬁeld studies. The coat colour of male giraffes, especially the blotches, darkens with age, but no studies have systematically mapped the colour transition with chronological age based on long-term data. We examine the value of using darkening coat colour as a biomarker of male age. We analyzed 33 years of data from 36 male Thornicroft’s giraffes, G. c. thornicroftii, living in Zambia in order to document key milestones in male development. We found that the change in male pelage colouration takes an average of 1.8 years and that males are completely covered with coal-black blotches at an average age of 9.4 years. Using lifetime data on male deaths and disappearances, combined with cross-sectional records on coat-colour transformation, we conclude that the average age of death among male giraffes is about 16 years old. The maximum lifespan of male giraffes is about 22 years compared with a maximum lifespan of about 28 years for female giraffes. We conclude that the possible proximate mechanisms and adaptive signiﬁcance of male coat-colour changes should be studied in more detail.
The full article can be downloaded from the Journal of Zoology website.