Adaptive colouration in wildebeests, part 10: photos worth a thousand words

https://depositphotos.com/283152392/stock-photo-masai-giraffe-white-bearded-wildebeest.html
This shows two coexisting ruminants which, at first head-scratch, seem to make no sense in terms of adaptive colouration. A hint: the crucial context may be not bright daylight but the darkness of night - seen through eyes more sensitive than ours.

https://www.alamy.com/stock-photo-a-confrontation-between-a-cheetah-and-a-wildebeest-in-the-grasslands-53666285.html
This shows, by the most direct photo-comparison, inconspicuous colouration vs adaptively conspicuous colouration. No large carnivore benefits from being conspicuous (with the partial exception of mature males of ecotypes of the lion, Panthera leo, living in open vegetation), but many species of gregarious ruminants have partly traded in their ability to hide from predators for the benefits of visibility-enhanced social means of dealing with predation.

https://www.alamy.com/stock-photo-blue-wildebeest-south-africa-70051987.html
This shows the most-brindled of any individual of any form of wildebeest, which is also the most-brindled of any wild ungulate, and in a looser sense about the most-striped of any ruminant. The darkness of mane and beard have been subsumed by the brindling, which even occupies the cheek. How does a large, gregarious ungulate, dependent on lawns for its food, benefit from the sort of colouration associated with crouching skulkers?

https://www.alamy.com/stock-photo-blue-wildebeest-brindled-gnu-white-bearded-wildebeest-connochaetes-76116481.html
This shows that wildebeests have extreme insignia in which females conform to males by growing horns, manes and beards, but nevertheless retain facial colouration so variable that each individual seems recognisable. How does a migratory, extremely gregarious ruminant with polygynous, promiscuous relationships and minimum sexual dimorphism derive adaptive benefit from continual recognition of kin and/or companions?

Posted on July 12, 2021 02:20 AM by milewski