These two saki monkeys currently reside in the Washington National Zoo. For those who are not versed in zoo history, the National Zoo was designed by Frederick Law Olmsted, who as a young man traveled through the ante-bellum south and left us about as unbiased a picture of the American slave holding culture as it was possible to gather - with the caveat that it was the slaveholders who put him up as he was traveling.
As far as the saki monkeys go, they are native to South America, mainly Brazil, French Guiana, Guyana, Suriname, and Venezuela. In fact, these are the white faced saki monkeys (Pithecia pithecia), with the male having the white face and the female being more subdued in the color - all the better to hide in the trees with the kids. You'll find some references that there are seven species of sakis, but there has been an eighth recently discovered.
What is particularly unusual about the saki monkeys is they, although being New World monkeys, do not have prehensile tails that can grab branches and so aid their lives in the trees. The tails are particularly long and bushy and they have especially furry faces. Most species of saki monkeys are not currently listed as endangered, although with their habitats getting reduced as the rainforests are pushed back further to make room for people, they are listed by the Internation Union for the Conservation of Nature (IUCN) as threatened.
Sakis spend most of their time high in the branches of the rain forests. They get about by making impressive leaps of over thirty feet, and spend a lot of their time looking for their food which is mostly plants - fruits, berries, and nuts - but also includes insects and at times small rodents. Perhaps in solidarity with their human cousins, they have no particular mating season but mate whenever they feel like it.
This rendering of the sakis in the Washington Zoo is in pastel on hot pressed water color paper. Note that when representing black or dark grey the rule of thumb is not to use black or dark grey, but instead stick to the blues. Beginning art students are at times even forbidden to use black at all and only when they reach more advanced stages do the teachers discretely pull them aside and sotto voce let them know it is all right to sometimes use black.
Believe it or not, the literature on saki monkeys seems a bit sparse and there is a lot posted on-line by zoos that house the sakis.
"Saki Monkey - Thick, Long-Coated Fuzzy Face", FactZoo.com, http://www.factzoo.com/mammals/saki-monkey-thick-long-coat-fuzzy-face.html
"Pale Headed Saki", Washington National Zoo, https://nationalzoo.si.edu/Animals/SmallMammals/fact-palesaki.cfm
"White Faced Saki Monkey", Lincoln Park Zoo, https://www.lpzoo.org/animal/white-faced-saki-monkey
"White-Faced Saki",Pittsburgh Zoo and PPG Aquarium, http://www.pittsburghzoo.org/animal.aspx?id=34
"White Faced Saki Monkey", Oregon Zoo, http://www.oregonzoo.org/discover/animals/white-faced-saki-monkey