Comparison between hamadryas and chacma baboon

(writing in progress)

The hamadryas baboon has a northerly distribution (https://upload.wikimedia.org/wikipedia/commons/b/b3/Hamadryas_Baboon_area.png), whereas the chacma baboon has a southern distribution (https://upload.wikimedia.org/wikipedia/commons/c/c3/Chacma_Baboon_area.png).

However, these species are more different than one might expect for members of the same genus.

Mature males of the hamadryas baboon are smaller than adult males of the chacma baboon, the body masses being respectively about 25 kg and 30 kg. However, adult males of the hamadryas baboon (while in their prime, but not later in life, when they become ‘elders’) look more massive than they really are. This is because a masculine cape in the pelage is better-developed in the hamadryas baboon than in the chacma baboon.
 
The tails also differ, that of the hamadryas baboon (https://www.shutterstock.com/nb/image-photo/female-hamadryas-baboon-papio-baby-wild-298940501) being thicker than that of the chacma baboon (https://www.alamy.com/cape-baboon-papio-ursinus-side-view-of-an-adult-male-walking-on-the-ground-mpumalanga-south-africa-image340586733.html), and having a tassel.
 
The colouration differs as follows.
 
Males of the hamadryas baboon are essentially grey, whereas those of the chacma baboon are essentially brown. The grey of the hamadryas baboon is particularly clear on its distinct fur-patches on the side of the head, which have no counterpart in the chacma baboon.
 
The face of males of the hamadryas baboon is flesh-coloured (https://depositphotos.com/364551778/stock-photo-big-family-hamadryas-baboon-road.html), whereas that of the chacma baboon is ‘black’ (https://en.wikipedia.org/wiki/Chacma_baboon#/media/File:Chacma_baboon_(Papio_ursinus_griseipes)_female_head.jpg and https://www.flickr.com/photos/lynfrancey/49994191022).
 
The most surprising differences are:

• Mature males of the hamadryas baboon have a female-like show of pink bare skin on the posterior. This makes them not just grey and caped, but actually colourful in a puzzling combination of masculine and feminine themes. And this pink posterior is offset and emphasised by whitish fur on the haunches, with no counterpart in the chacma baboon.
• The hamadryas baboon shows eye-Whites to some extent. By contrast, the chacma baboon does not, because the sclera is darkly pigmented.

The following, of an adult male (https://c2.staticflickr.com/8/7277/8155808500_752b8c07ae_b.jpg), shows the flesh-coloured face, pale grey hairdo (covering the ears), grizzled darker-grey cape, tassled tail, and conspicuous contrast on the posterior (between pink bare skin and whitish pelage). Also see https://depositphotos.com/79002692/stock-photo-wild-hamadryas-baboon.html.
 
The following shows: dark face, lack of distinctive pelage on side of head (leaving the ears visible), absence of cape with just a hint of a tuft of longer fur on the nape, thin tail lacking tassel, lack of any noticeable colouration on posterior.
 
adult male: https://www.alamy.com/stock-photo-chacma-baboon-walking-and-looking-at-camera-kruger-national-park-south-32164293.html

https://www.warwicktarboton.co.za/other%20crea%20pgs/128ChBab.html

Both the hamadryas baboon and the chacma baboon have extremely large and sharp canines in adult males. The canines are unremarkable and relatively harmless in adult females. Both species are equally sexually dimorphic in this respect.
 
In both species, when males punish females and juveniles in the group. This is done by nipping with the stout incisors, not the canines.
 
The following, of an adult male of the hamadryas baboon, shows: ears are hidden by pale grey hairdo; ‘honing-stone’ lower premolars, against which the upper canines are continually whetted, in contrast to ‘normal’ premolars immediately posterior to them; facial skin is flesh-coloured.
 
adult male: https://www.istockphoto.com/photo/yawning-hamadryas-baboon-gm1129675047-298507191
 
The following, of an adult male of the chacma baboon, shows: ears are drawn back so far that they become inconspicuous; upper gums are exposed during ‘fang-baring’ yawn; facial skin is ‘black’ except for pale eyelids.
 
adult male: https://www.flickr.com/photos/wildafrica/260517694

(writing in progress)

Posted on 08 de julho de 2022, 02:48 AM by milewski