Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"
I'm going to see how many of Africa's monkeys I can cover! I hope you don't get bored … but our monkeys are so diverse, interesting and pretty, I'm reasonably confident you won't! Case in point, our monkey of the week – the Crowned Monkey, or Crowned Guenon, Cercopithecus (mona) pogonias. It is very distinctive with its bright orange-yellow, poofy cheeks which make it look rather grumpy, and the light-fringed black ridge it has running down the centre of its crown. Other features are its pointed eartufts and its generally bright orange-yellow underside, with black hands and feet, a dark stripe running along the outer sides of its arms, and another dark stripe running down its back and continuing onto its long tail. The sides of its torso and thighs are coloured a grizzled olive to brown. Crowned monkeys are fairly small: males reach 10.5 lbs/4.8 kg and females 7.9 lbs/3.6 kg.
The Moaning Monkeys
The crowned monkey belongs to a distinctive group of equatorial African monkeys called the 'Mona monkeys'. Sometimes they are all regarded as a single species, Cercopithecus mona, but genetic and other evidence shows significant differences between them that warrant dividing them into at least six species: Mona, Campbell's, Lowe's, Dent's, Wolf's and Crowned. The entire group is spread out over the tropical rainforest of West and Central Africa. They do not tolerate seasonal differences, either in temperature or rainfall, thus being only present in the always-hot-and-moist rainforests, not venturing into seasonally dry forest or cool montane forests. But they do inhabit well-developed riverine forest and thus can use the lush growth along riverbanks to enter otherwise unsuitable savannah country. The six species or subspecies partition the rainforest block between themselves, each kind inhabiting a particular stretch, to the exclusion of the others. The part inhabited by the crowned monkey, is pretty much right in the centre, to the north and west of the great Congo/Zaire River. To its east occurs Dent's monkey, to the south Wolf's monkey, and to the west, the proper Mona monkey. It seems to be, along with Wolf's monkey, the most recently evolved species of the group.
The mona monkeys are named, as far as I can tell, for the moaning calls uttered by the females – though males also utter these calls. Each species has its own repertoire of additional calls. In the crowned monkey, these include a loud 'hack' uttered by the male as a territorial call; a loud boom, which carries far through the forest, and helps the troop members to rally back together after having dispersed, for instance if they fled from a predator; the miaowing calls made by males and females, which also serve to keep the group together, and a number of whining calls that can be modulated to communicate different messages.
The entire group of mona monkeys is highly arboreal, relying on an unbroken canopy so they can move from tree to tree without having to come to the ground. Their small hands and feet are deft and their joints very flexible, making them excellent climbers. Because of being up in the trees all the time, they are mostly preyed on by eagles, such as the powerful Crowned Eagle. They eat mainly fruit, supplemented with some insects like grasshoppers, beetles and caterpillars. They typically start the morning with fruit; in the hot mid-day they hunt insects in the shade, and in the cooler afternoon and evening they return to seek fruits. They live in groups headed by a dominant male. He is not as significantly bigger and stronger than the other males, as happens in mandrills and some other monkeys, and doesn't play as active a part in defending his troop, instead serving as a lookout giving warning of danger.
All the mona monkeys have bold patterns of fur and skin on and around their faces. This is used for communication, the monkeys striking characteristic poses to each other. In the case of the crowned monkey, these include jerking of the head to the left and the right, the 'crown' being impressive if shown in profile. Other mona monkeys use poses in which they successively expose and conceal their faces and the bright fur on their breasts.
These monkeys are alert, inquisitive and curious. They interact much with each other, and will even take an interest in, and interact with and respond to other monkey species, and indeed also birds, squirrels, and even insects! But they're most attentive to members of their own group. Troops are very close, and often sleep all huddled together.
For the moment, the crowned monkey and the other species of the mona monkey group are reasonably safe. They're small, high up in the trees, and able to rapidly flee and conceal themselves, making them hard targets for hunters, and not yielding much meat. But they're of course vulnerable to the forest being cut down completely; they can't survive in treeless land. Thus, their conservation is dependent on the conservation of the African rainforests themselves, which shelter and nurture a vast number of other fascinating species as well.