The puzzle of conspicuous pallor in a Sahelian giraffe, part 2: as opposed to masculine darkness

To understand the pallor in Giraffa camelopardalis peralta (see my last Post), it may also be useful to review the masculine darkness that occurs in most forms of giraffe.

In full maturity, male giraffes become much larger-bodied than adult females: they can weigh up to 1.5 tonnes as opposed to the average 0.8 tonnes of their mothers. They also darken and produce odours from skin glands ( and and

Darkness and smelliness are individually variable ( However, the pattern of sexual dimorphism in giraffes is such that males combine:

Estes (1991, page 203) confirms that "Rival bulls recognise and react to one another from a long way off, demonstrating the capability of long-distance communication".

The changes in males at the peak of masculinity detract from their camouflage. However, this poses no particular puzzle, because:

  • it is normal for males, particularly in sexually dimorphic species, to trade off security for sexual advantage,
  • masculine self-advertisement needs not compromise the camouflage of females and juveniles, because giraffes are only loosely gregarious and dark males tend to be solitary (, and
  • males may be less vulnerable than females to predation by day, and dark figures (although conspicuous in bright light) remain inconspicuous by night.

It is noteworthy that the various flags (see tend to remain despite the overall darkening in mature males.

Another noteworthy finding is that, in maturing males of Giraffa tippelskirchi tippelskirchi, the whole head remains pale in some individuals (e.g. and and

The following illustrate various degrees/extents of masculine darkness in various species and subspecies of giraffes:

Giraffa giraffa giraffa and and

Giraffa giraffa angolensis

Giraffa tippelskirchi tippelskirchi
scroll in and

Giraffa tippelskirchi thornicrofti

Giraffa reticulata

Giraffa camelopardalis camelopardalis

Giraffa camelopardalis rothschildi

If it is true that masculine darkness is poorly-developed in G. reticulata, this is in line with the observation that this is the species of giraffe possessing the greatest uniformity in various aspects of its colouration.

We need more information for G. c. peralta. The few photos available suggest that the blotches do darken in mature males (see e.g. However, this is not enough to give the figure a dark aspect overall, because the matrix seems to remain as pale as in females and immature males.

Masculine darkness in giraffes does not necessarily contradict the idea that the conspicuous pallor of G. c. peralta of the Sahel/Sahara represents a basic adaptive shift among giraffes. It is this pallor, rather than masculine darkness, that is an important exception to any generalisation that the colouration of giraffes functions as camouflage.

Posted on Νοέμβριος 19, 2021 0512 ΠΜ by milewski milewski


Αναρτήθηκε από milewski πάνω από 1 χρόνo πριν (Αναφορά)
Αναρτήθηκε από milewski πάνω από 1 χρόνo πριν (Αναφορά)
Αναρτήθηκε από milewski πάνω από 1 χρόνo πριν (Αναφορά)

Προσθήκη σχόλιου

Συνδεθείτε ή Εγγραφή για να προσθέσετε σχόλια