Going Ape

Kris: Thanks for the De Brazza - let me put up another very colourful set of primates (all endangered): the douc langurs of Vietnam. Below is one of the 1987 WWF issue:



This is the red-shanked species (also on the earlier Vietnam 2014 primates issue), sometimes seen in Western zoos - they are very hard to keep because of their diet - they are leaf-eaters. I saw them in Cologne Zoo in Germany, and in the Endangered Species Center near Hanoi, where they also ahd the grey-shanked species. The third, and probably the rarest, is the black-shanked species.

Here is a grey-shanked douc:


And a black-shaked one:


The photo above is by Tilo Nadler, who works for the Frankfurt Zoo and is still, I think, the director of the Center for Endagered Species I visited and where he kindly showed me around. Animals at the centre are mostly confiscated from hunters or markets and kept for breeding, safety (sad to say) and for re-introduction.
This

Some more red-shanked doucs:

As one of the 1995 UN Endangered Species issue:




and on a rather rare issue of 2014 of laos which also shows the saola, next to the douc, known almost excusively from skulls obtained from hunters and one captive animal that soon died (and is now, stuffed, at Hanoi University - another captured animal also soon died) and only photographed once or twice in the wild.

Sorry - I wanted to add a picture of a red-shanked douc:

Another member of the Genus Cercopithecus (C. diana) native to the forests of western Africa, but in a rather smaller range than C. neglectus. Are the Diana monkeys very different in color? I'm assuming the one on the stamp is female, the one in the picture I found, male. Also belongs to the set of 4 by the Republic of Guinea. Cobie, Glad you like some of my contributions; it's always more fun when there is a response to one. Now that you have crossed the magic threshold of 50, let me know if you would enjoy mail contact.

Hi Kris: My guess is that the stamp has faded a bit and may never have been a very good colour, as in the picture.

The guenon are very colourful too, with their faces that may be maked with white whiskers, white noses or blue skin, and fur that may contain golden or russet. Here are some 2013 WWF issues from Guine-Bissau of Campbell's guenon (Cercopithecus campbelli):








You don't see them in zoos very often - the Jardin des Plantes in Paris had some some years ago.

And yes, it would be nice to exchange e-mails and learn more about each other and our stamp hobby! Not sure how to go about it - do you know?

Best wishes, Cobie

Hi Cobie, Here is the third monkey in the set issued by the Republic of Guinea, another member of the genus Cercopithecus (C. aethiops). Also known as the Grivet, it lives in drier regions of East Africa. Again, some remarkable blue skin coloring. Do you happen to know if these, and other, monkeys are able to see the color blue particularly well? ((P.S. for contact, just click my name))

Hello Kris:

All old world primates have human-like colour vision based on red, blue and green sensitive retinas but not all American monkeys have, even within the same species. Some squirrel monkeys are what in humans would be called colour-blind, that is, they lack one class of colour sensors. Despite this, they seem (like humans) to get by and survive very well.People have tried to explain colour vision's evolution but I am not very convinced. The original mammals were nocturnal and day-light sensitive receptors had to evolve, and these seem to be colour sensitive but not all animals see colours like humans, such as dogs and horses; only Old World monkeys (and apes) do. People often talk about ripening fruit as an important stimulus but not all ripe fruits are red or blue, or even yellow; and humans tend to forget smell, which is better in monkeys. In the guenons, white fur and blue skin with red touches is thought of a signal especially in the forest (like white tails on deer) but I like to think of colour vision as primates have it as one of those nice changes in evoloution - it made worlds much more colourful without killing of the owners of the new mutation ; the different face patterns of the guenons are thought to help species recognition (and breeding, although hybrids occur often where distribution areas overlap!).
Here is an issue from Liberia from 2001:




It shows (apart from the Diana monkey) four species of guenon: Lowe's, Wolf's, The red-eared, and the moustached guenon.
Lowe's is another name for Campbells' guenon, above.





Above is a Wolf's guenon. Below, red-eared and moustached guenons:

What happened to my Liberia picture? Let's try again...

Excellent thread, I am enjoying all the posts.



Would teh blue colouring suggest a chemical or hormonal influence dependant upon what the Grivet ate (what nuts or berries perhaps?) or a leftover spray of pheromes?

Scent does drive humans as well as other animals.

Hello Cobie, Fascinating info on color, thanks; and the Liberians are great. I've always been interested in the complexities of the retina and vision, and am amazed at how differently animals perceive their surroundings. We've heard about a dog having a keener nose than we do, and there Puzzler is certainly right on track (excuse the pun), but I think differences in vision are at least as important.
Here is the 4th in the Republic of Guinea set with the southern Talapoin (Miopithecus talapoin; note odd spelling). Its range lies further south than that of the other set members, along the Congo. It's quite small and probably blends in well with its surroundings, being greenish-brownish, without any special highlights.

Hello Kris (and Puzzler): There is probably a hormonal influence on the blue and red skin colouring in primates; a good example is the male mandrill whose snout is brighter that that of the females; OTOH, some macaque species have red faces and the colour becomes more intense when the females are receptive; older animals seem to get more red in the face too (Japanese snow monkeys are one example). But I have noticed that light blue skin areas occur on the body of some monkeys, in no regular pattern.

I like the talapoin, Kris - you rarely see them on stamps since they are not very flashy, or big - they are among the smallest Old World monkeys, perhaps the smallest. Perhaps because of that, they live in more marginal forest areas and swampy mangrove like regions of the Congo basin. They have adpated to forest disturbance and humans as well. There are two species, the Northers and Southern talapoins. I have seen them in Barcelona zoo.

here's apicture of the best blue and red in primatedom, from the 1991 WWF Equatorial Guinea set:

I remembered seeing some recent papers on face colouring in primates. One is by Santana et al, in Nature Communications vol. 4, 2013.

Abstract:
The faces of Old World monkeys and apes (Catarrhini) exhibit every possible hue in the spectrum of mammal colours. Animal colouration experiences selection for communication, physiology and ecology; however, the relative importance of these factors in producing facial diversity in catarrhines is not known. Here we adopt a comparative approach to test whether facial traits have evolved in tandem with social, geographic and ecological pressures across four catarrhine radiations. Our analyses reveal the underlying correlates of two major axes in the evolution of facial diversity. Facial colour patterns are linked to social factors, such that gregarious and highly sympatric species have evolved more colours in their faces. Facial pigmentation tends to be dominated by ecological factors, and species living in tropical, densely forested and humid habitats in Africa have evolved darker faces. Thus, both sociality and ecology have played a role in producing the highest diversity of faces within mammals.
The figure below, from that paer, helps with the abstract:




For many years, Jonathan Kingdon has been studying not just faces but also body colouration in African guenons, and suggested how these developed. Most recently, he has been one of the ditiors of a series of volumes on African mammals. One volume concerns primates, and combines Kingdon's scholarship with his talent as a wildlife artist, which may be familiar with some of you who know his "(Pocket) Guide to African Mammals', or his monumental "Mammals of East Africa". The new book has all of their charm as well as many sketches from his filed notes.

Here is an example of his monkey "colour schemes":






I can recommend his books although the older ones are hard to find, and the new Mammals of Africa, even as a single volume, is rather expensive. But if you are interested in primates, see if your locallibrary or university library stocks it. Those and the new "Handbook of the Mammals of the Wordl" (Vol. 3 is all about primates).

One more, than I'll try and find spome stamps to bolster the argument . The following figure is from a more recent paer by Allen et al., also in Nature Communication, in 2014.
"Character displacement of Cercopithecini primate visual signals"

Abstract:
Animal visual signals have the potential to act as an isolating barrier to prevent interbreeding of populations through a role in species recognition. Within communities of competing species, species recognition signals are predicted to undergo character displacement, becoming more visually distinctive from each other; however, this pattern has rarely been identified. Using computational face recognition algorithms to model primate face processing, we demonstrate that the face patterns of guenons (tribe: Cercopithecini) have evolved under selection to become more visually distinctive from those of other guenon species with whom they are sympatric. The relationship between the appearances of sympatric species suggests that distinguishing conspecifics from other guenon species has been a major driver of diversification in guenon face appearance. Visual signals that have undergone character displacement may have had an important role in the tribe's radiation, keeping populations that became geographically separated reproductively isolated on secondary contact.

Thank you for all of the diverse information.
Wonderful topic.

Hi Cobie, Thanks for the great information! The New World monkeys haven't been seen much on this thread yet, so here is one of my favorites: the Emperor Tamarin (Saguinus imperator) of the southwestern Amazon region. Supposedly named after the last Kaiser of Germany, Wilhelm II, (try this: Kaiserschnurrbarttamarin) because of his mustache (color picture). There was also a King Wilhelm II of Baden-Württemberg at the same time and maybe his beard is more of a model? Visit the Moustache thread for some more lovely examples.