Photo nicely showing abruptness of transition between infantile and adult colouration in baboons

@dejong @tonyrebelo @jeremygilmore @ludwig_muller @beartracker @davidbygott @jacqueline_llerena @dinofelis

In all species of baboons, infants have distinctive colouration (https://www.flickr.com/photos/robsall/8739109282).

In most cases, infants are far darker in the pelage than are adults. The face, ear pinnae (https://www.alamy.com/stock-photo-female-and-baby-chacma-baboon-papio-ursinus-kruger-national-park-south-20547777.html), fingers/palms/soles, and ischial callosities are pale pinkish - in contrast with what, in most species of baboons, is dark bare skin in these places in adults (https://dailywildlifephoto.nathab.com/photos/1130-baby-and-mama-baboon-04-18-2016 and https://www.istockphoto.com/photo/chacma-baboon-baby-south-africa-gm171221149-20382033).

Papio anubis
https://www.dreamstime.com/olive-baboon-baby-papio-anubis-cercopithecidae-old-world-monkey-high-quality-photo-image187008883
https://www.alamy.com/olive-baboon-papio-anubis-female-holding-baby-masai-mara-game-reserve-kenya-october-image263064018.html
https://www.shutterstock.com/nb/image-photo/olive-baboon-baby-papio-anubis-cercopithecidae-1765805159

Papio ursinus
https://www.mindenpictures.com/stock-photo-chacma-baboon-papio-ursinus-baby-nursing-kruger-national-park-south-naturephotography-image00451436.html
https://www.masterfile.com/image/en/841-02717684
https://www.agefotostock.com/age/en/details-photo/cute-baby-chacma-baboon-papio-hamadryas-with-its-mother-south-africa/ESY-030174950

Papio hamadryas
https://m.facebook.com/heraldsun/photos/-introducing-melbourne-zoos-newest-baboon-babies-makali-and-quill-these-two-name/10156788269113171/
https://www.zooborns.com/zooborns/baboon/

Mandrillus sphinx
https://wdwnt.com/2020/07/photos-video-baby-mandrill-born-at-disneys-animal-kingdom/

Theropithecus gelada
https://www.zooborns.com/zooborns/gelada/
https://www.redbubble.com/i/ipad-skin/Baby-Gelada-Baboon-by-Sparky2000/3919076.MHP6F
https://www.youtube.com/watch?v=Fdjy-c-EFX0
 
In the kinda baboon (Papio kindae, https://www.inaturalist.org/taxa/557988-Papio-kindae), the pelage of infants is whitish instead of blackish (http://www.whitewolfpack.com/2012/10/white-baby-baboon-found-in-zambia-photos.html and https://www.edwardselfephotosafaris.com/wildlife-luangwas-white-baboons and scroll in https://www.intrepidtravel.com/adventures/zambia-travel-safari/). However, the principle is the same: as in all baboons, infants provide dark/pale contrast with adults.
 
This conspicuous colouration in infants is fairly well understood by primatologists.

The emotional effect on adults is evident. A mature male can use this as a ‘pacifier’, just by grabbing and holding an unfortunate infant when being attacked by rivals. This seems to function as a figurative rather than literal shield, on the basis of 'emotional blackmail'. The protective instinct evoked by the dark/pale contrast is so strong that it inhibits macho anger.

Indeed, mature males seem to ingratiate themselves with certain mothers, so as to be able to use (actually, abuse) the infants as shields when needed.

This is odd behaviour from a human perspective. The associated instinctive reactions go well beyond protecting infants, spilling into a wider realm of social interaction, involving sexual politics, and sometimes selfishly causing inadvertent harm to infants.

Males of baboons do not exhibit paternal care in any direct sense, in the way canid fathers do (https://www.jstor.org/stable/3883039#:~:text=Paternal%20care%20has%20never%20been,commonest%20forms%20of%20male%20care.). However, they seem to be emotionally affected by the appearance of infants, triggered partly by the distinctive colouration.
 
With this in mind, I was delighted, by sheer chance, to find this 'photo-in-a-million': http://static.wixstatic.com/media/04e4eb_2c247c23bcaa42cfabd8cf1432cfddcf.jpg_256.

It shows how extremely abrupt the transition is from infantile to juvenile colouration (the latter being identical to that of adults, https://www.istockphoto.com/photo/olive-baboon-infants-having-dinner-in-serengeti-national-park-tanzania-gm1370705240-440199827?phrase=monkey%20embracing%20baboon%20two%20animals) in Papio ursinus.

The juvenile on the right seems hardly bigger than the infant on the left, and yet the transition is categorical. Presumably no mature male, grabbing this juvenile, is going to extract any indirect protection from it, if attacked by other males.
 
Here we see the expected dark/pale contrast between the pelage and the bare skin within the infant. It is the difference in colouration from the juvenile stage that is remarkable. The infantile colouration seems to be strictly timed during the growth of the animal.
 
I am not the first to document this topic in general. However, I have not seen the following wo aspects pointed out in the literature:

• one of the reasons why the appearance of infants is so evocative is that, in contrast to other members of their group, they alone have clearly visible eyes, and
• the benefits of infantile colouration, relative to its costs in terms of masculine abuse, may last only briefly, after which the colouration is lost remarkably suddenly.

The irides (https://en.wikipedia.org/wiki/Iris_(anatomy)) of the infant seem to be brown, as in adults. However, the facial skin is so pale that the eyes stand out in the face (https://www.alamy.com/stock-photo-baby-chacma-baboon-papio-ursinus-playing-on-ground-in-kruger-park-81045478.html and https://www.canstockphoto.com/baby-chacma-baboon-29261119.html) - an effect obscured at all other ages/stages of growth in baboons.
 
Imagine a naturalist touring e.g. Kruger National Park, with the express goal of taking such a photo, capturing this abrupt transition in colouration. How many hours of endeavour would it take to find such convenient framing?

This photographer was remarkably lucky, and he/she may not realise the illustrative value of the photo.

Posted on 08 de julho de 2022, 08:19 AM by milewski