enzh-TWfrderues

Moos’ Blog


Bio­di­ver­sity Counts!
Obser­va­tions and opin­ions con­cern­ing zoos, evo­lu­tion, nature con­ser­va­tion and the way we treat/​support the ecosys­tems which are sup­posed to serve us.

201224Jul10:38

There is no such thing as grey­ing in Giraffes, they just get darker while aging

pub­lished 24 July 2012 | mod­i­fied 18 Decem­ber 2016

Phil Berry’s 33 year of doc­u­ment­ing of Thornicroft’s giraffes (Giraffa camelopardalis thorn­crofti) led to the sci­en­tific con­clu­sion that the male giraffe’s pat­tern of brown blotches grows darker with age. The unique set of record­ings were started by Phil Berry when he became a park ranger in east­ern Zambia’s South Luangwa Val­ley in the 1970s. It is the only place where this sub-​species of giraffe can be found. No more than 1,500 remain in the wild, and none are kept in zoos.


ARKive photo - Thornicroft's giraffe

It’s pretty amaz­ing that he’s sim­ply writ­ten down tons of stuff for over three decades that we are now able to turn into sci­en­tific papers

(Prof Fred Bercov­itch, Pri­mate Research Insti­tute and Wildlife Research Cen­tre, Kyoto Uni­ver­sity, Japan) »

The researchers who accessed the 33 years of data ana­lyzed infor­ma­tion from 36 male Thornicroft’s giraffes, and pub­lished their find­ings in the Jour­nal of Zool­ogy, recently. By com­par­ing recorded colour changes, they were able to gen­er­ate a life-​history pro­file for the ani­mals. All species of giraffe are known to develop darker coats as they age but the exact tim­ing of the changes were unknown. They found that males’ coats first started to change colour at seven to eight years of age and brown blotches trans­formed to coal-​black within two years.Males of the species reach sex­ual matu­rity at approx­i­mately 10 years, lead­ing Prof Bercov­itch to sug­gest that the ini­tial dark­en­ing phase indi­cates a “com­ing of age”. “I sus­pect that the black­en­ing of the blotches is a pub­lic announce­ment to the other giraffe that a male is going through puberty — some­thing like ado­les­cent boys flex­ing their mus­cles to impress the oppo­site sex.” The authors of the study there­fore sug­gest that the dark­en­ing is linked to testos­terone upsurges asso­ci­ated with puberty.

The researchers were also able to con­clude that the aver­age age of death among male giraffes is about 16 years old, and that the max­i­mum lifes­pan of male giraffes is about 22 years. Which is con­sid­er­ably shorter than the max­i­mum lifes­pan of about 28 years for female giraffes.


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Tiger map” (CC BY 2.5) by Sander­son et al., 2006.

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