Speciation of wildebeests across the dark-pale divide

 

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Connochaetes mearnsi photo ©  Stefan Swanepoel

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Connochaetes albojubatus adult male photo ©  Paul Mannix

 

Two species of white-bearded wildebeests in East Africa have diverged categorically in how they achieve whole-body conspicuousness at a distance. Although both rely on gloss-versus-gloom effects as well as pigmentation, the western species looks dark overall whereas the eastern species looks pale overall. This fits an overall pattern seen in migratory hoofed mammals adapted to either mesic or semi-arid habitats.

 

Robin and the Honey Badger, 22 March 2016

 

Photographs:

Pale white-bearded wildebeest (Connochaetes albojubatus)

Dark white-bearded wildebeest (Connochaetes mearnsi)