Differences in the pelage on the ear pinnae between Coke’s hartebeest (Alcelaphus cokii) and the Cape hartebeest (Alcelaphus caama)

7 August 2026 | Work in Progress

By Antoni V Milewski and Anthony J Mills · Originally published 30 July 2026

About this edition. This is Antoni Milewski’s post, republished with his permission. Only the photographs he chose are used. Those on iNaturalist under a Creative Commons licence are shown; the rest are hosted externally and are given as links. No images have been substituted. Read the original on iNaturalist.

(writing in progress)

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The whitish pelage on the anterior surface of the ear pinna in Alcelaphus cokii seems to differ from that in Alcelaphus caama by opening (presumably in hot weather) to expose the dark, bare skin.

In A. caama, this opening mechanism seems absent.

ALCELAPHUS COKII

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ALCELAPHUS CAAMA

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Posted on July 30, 2026 12:10 PM by
milewski

Addenda from the thread of comments

The author added the following in comments beneath the original post.

@christiaan_viljoen

Do you think this location is Bushman’s Kloof?

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Shift

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Alcelaphus buselaphus cokii, Mara, Kenya, by bradleyfishes
Bradley RasmussenMara, Kenya · 24 Sep 2024CC BY-NCobs. 246499190
Alcelaphus buselaphus cokii, Narok County, Kenya, by mikeloomis
mikeloomisNarok County, Kenya · 5 Oct 2007CC BY-NCobs. 19483935

@mionectes

I agree that it is parsimonious to assume B. tragocamelus, rather than some far-fetched giraffid.

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Laikipia

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Is the following in the Laikipia region?

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Catoptric effects

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Buccal semet

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Excellent

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Credits. Photographs reproduced from iNaturalist are shown under the Creative Commons licence stated in each caption and remain the copyright of the observers named. All other images cited by the author are hosted externally and are linked, not reproduced.

By Antoni V Milewski and Anthony J Mills. Text by Antoni V Milewski, posted on iNaturalist 30 July 2026 and republished here with permission. Read the original.