Adaptive colouration in wildebeests, part 1: an introduction to large-scale, conspicuous features

Most species of ungulates have certain inconspicuous features and certain conspicuous features of colouration, depending on the range/scale.

Wildebeests (Connochaetes, are relatively large-bodied, extremely gregarious, and typically found in open vegetation. This leads to the questions:

  • what is the overall effect at a distance, and
  • how does this differ among the various species and subspecies?

All forms of wildebeests have some degree of brindling (, which in principle serves to detract from conspicuousness ( However, this is usually outweighed by features of colouration that are adaptively conspicuous to scanning predators by day.

For example, mearnsi ( advertises itself rather than trying to blend into the background ( and

What is particularly noteworthy about this genus is the diverse ways in which the dark/pale contrasts have been achieved.

So, let us examine adults of the various species/subspecies (

In gnou (, conspicuous overall darkness ( and and is achieved mainly by a poorly-understood anti-sheen quality of the pelage. This is based on the physical structure of the hairs as much as their pigmentation.

In other forms of wildebeest, this anti-sheen effect is less extreme, and is combined with a sheen effect on the rump (broadly-defined).

This combination of anti-sheen and sheen is most easily illustrated in mearnsi. The figure combines overall darkness with a pale-looking rump (

The impression of pale on the rump is produced by sheen rather than depigmentation ( and and and and scroll in and and

In albojubatus (, the beard and cheeks are conspicuously pale relative to the dark front of the face ( and and

In taurinus, the figure tends to look dark, with some degree of paleness owing to sheen on the rump. However, this is possibly the form with the least conspicuous colouration, overall ( and and and

In mattosi (, the dark mane is permanently erect. This, in combination with the dark beard and front of the face, gives the anterior of the figure in profile a conspicuously dark emphasis ( and

In johnstoni ( there is, in some individuals, a bold whitish (depigmented) bar on a dark-pigmented face ( and

In cooksoni (, the front of the face is conspicuously dark relative to the pale forequarters (e.g. see fourth photo in

Returning to gnou:

Both the mane and the tail can be conspicuously pale, by way of depigmentation.

The overall result is as follows:

To be continued in

Publicado el julio 9, 2021 12:09 MAÑANA por milewski milewski


The following shows that the tail of Connochaetes gnou can be truly white: However, this may be somewhat unnatural, given that these horns are also unusually pale.

Publicado por milewski hace alrededor de 3 años

The following shows that juveniles of Connochaetes gnou develop the paleness of the tail before the infantile paleness of the feet has been lost:

Publicado por milewski hace más de 1 año

In albojubatus, the sheeny paleness on the rump is present ( However, it is not particularly noticeable. This is because a) the ground colour is relatively pale overall ( and, and b) the hindquarters are broadly medium-tone greyish (

Publicado por milewski hace más de 1 año
Publicado por milewski hace más de 1 año
Publicado por milewski hace más de 1 año

The following is labelled as mearnsi. However, I suspect that it is actually albojubatus, perhaps in Tarangire National Park:

@capracornelius @tandala @zarek
What would be your identification?

Publicado por milewski hace más de 1 año
Publicado por milewski hace más de 1 año
Publicado por milewski hace más de 1 año

In taurinus, all conspicuous features, other than the darkness of the front of the face and of the tail, are weakly expressed. However, this form can be dark enough, overall, to be conspicuous at a distance in open vegetation.

Publicado por milewski hace más de 1 año

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