The three alcelaphin bovids of the Serengeti: a comparison of adaptive colouration, part 2

...continued from


Anterior auricular flags refer to the anterior surface of the ear pinnae (usually viewed from in front of the figure), whereas posterior auricular flags refer to the posterior surface of the ear pinnae (usually viewed from behind the figure).

An alcelaphin elsewhere, namely Damaliscus pygargus phillipsi, possesses a posterior auricular flag.

However, the posterior surface of the ear pinnae is not conspicuous in any of the three species in the Serengeti.

In C. mearnsi, this surface is dark, except for its proximal ventral portion ( and This is present already in infants ( This is precocial, being present already in jnfants (

In D. jimela, the surface in question has a dark tip, the extent of which is individually variable ( and and and and

However, there is no dark/pale contrast or, as far as I know, sheen.

In A. cokii, the surface in question is plain fawn, similar to the ground-colour (

Turning to the question of anterior auricular flags:

The anterior surface of the ear pinnae has whitish hairs in all three species, which is potentially conspicuous, depending on distance and illumination:

Connochaetes mearnsi (in which the ear pinna seems peculiarly narrow): and

Damaliscus jimela: and

Alcelaphus cokii: and

In summary, the ear pinnae of the three species have definite colouration. However, the only species in which the ear pinnae are somewhat conspicuous is D. jimela, in which the whitish front-of-ear can, in certain illuminations and at certain distances, contrast with the dark of the face.


Pedal flags are absent in adults of all three alcelaphin bovids of the Serengeti.

This is true notwithstanding the clear pattern in adults of D. jimela, in which the lower legs and carpals are differentiated from the upper legs ( and and

Damaliscus jimela lacks a pedal flag, because the lower legs

  • are not depigmented enough to be conspicuous in terms of pale vs dark (as opposed to hue), and
  • do not seem to be sheeny.

However, infants and juveniles of C. mearnsi have conspicuously pale lower legs, owing to a combination of depigmentation and sheen ( and and and and and and and and and


All three alcelaphins in the Serengeti possess dark tail-tassels.

Furthermore, in A. cokii the tail-tassel is one of only two parts of the figure that are blackish (

However, caudal flags are poorly-developed in all three species.

In C. mearnsi, the tail-tassel is large, and it is demonstrative in that it is swished during running, prancing and cavorting ( and and

The following show the relative sizes of the tail-tassels in A. cokii and C. mearnsi ( and The tail of C. mearnsi is perhaps the proportionately longest of any ruminant on Earth, reaching ground-level.

However, the tail of C. mearnsi

In D. jimela and A. cokii (, the tail-tassel is relatively small, and the tail is undemonstrative.

In D. jimela, the tail is held approximately horizontal by mature males in the courtship display ( Please also see comments in part 3.

In A. cokii, the tail is so slight that its blackish tassel


An alcelaphin elsewhere, namely Damaliscus pygargus phillipsi, possesses an abdominal flag.

A hint of this pattern can be seen in the following, of

However, all three species in the Serengeti lack abdominal flags.


A buccal semet may be present in adults of C. mearnsi, consisting of the contrast between the relatively dark mouth and the relatively pale beard (

This works because the beard extends right up to the mouth, offetting the movements of chewing.

A different buccal semet may possibly occur in juveniles.

The following further illustrate the colouration of the mouth in C. mearnsi ( and and and

A buccal semet is absent in D. jimela ( and and

However, A. cokii clearly possesses a buccal semet ( and and and and and

The following shows that, in A. cokii, the lower lips are the only part of the animal, other than the tail-tassel, with blackish pelage (

The following shows the typical situation in which the buccal semet is relevant (

The following footage, although belonging to a different species (Alcelaphus caama), shows the activation of its buccal semet ( and

ADDITIONAL PHOTOS OF ALCELAPHUS COKII (also see comment in part 3)

I have described the colouration of C. mearnsi and D. jimela, but not A. cokii, in previous Posts. The following photos further illustrate A. cokii.


The following shows that, in C. mearnsi, the darkness conferred by anti-sheen is conspicuous at distances ranging from 50 metres to half a kilometer (

Alcelaphus cokii and D. jimela have some degree and extent of anti-sheen.

However, D. jimela - which is more intensely pigmented than A. cokii - does not emulate C. mearnsi in seeming dark at distance (

Part of the explanation for these differences is that C. mearnsi is migratory and extremely gregarious, whereas A. cokii is sedentary and only moderately gregarious.

The following compare the colouration of A. cokii with that of Eudorcas thomsoni nasalis - which possesses a lateral bleeze, making this gazelle unambivalently conspicuous.

The lateral pattern of E. t. nasalis qualifies as a bleeze, and not merely as a flag. This is because it

  • occupies a large proportion of the figure, and
  • is based on extremes of pigmentation/depigmentation, making it conspicuous under various illuminations.

The last photo in shows that the lateral bleeze of E. t. nasalis is more conspicuous than any feature of A. cokii.

The moderate pigmentation of the rump, vs moderate depigmentation of the buttocks, in A. cokii cannot rival the boldness of the pattern in E. t. nasalis (, when the pale surfaces of A. cokii show sheen, its figure can rival that of E. t. nasalis in conspicuousness (

All of the genera of alcelaphins represented in the Serengeti show great variation in colouration, depending on species/subspecies. In the case of Connochaetes, C. mearnsi is second only to Connochaetes gnou in overall conspicuousness, despite falling short of Connochaetes albojubatus in terms of a facial flag.

In the case of Damaliscus, D. jimela is not as conspicuous as Damaliscus pygargus, but more so than Damaliscus lunatus.

In the case of Alcelaphus, A. cokii is not as conspicuous as A. caama and Alcelaphus swaynei, but more so than Alcelaphus lelwel and Alcelaphus buselaphus.

To be continued in

For an index to my many Posts about the genus Damaliscus, please see

Publicado el abril 9, 2023 11:42 MAÑANA por milewski milewski


Publicado por milewski hace más de 1 año

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