Animals Wildlife Meet the Planet's 25 Most Endangered Primates By Russell McLendon Senior Writer University of Georgia Russell McLendon is a science journalist who covers a wide range of topics about the natural environment, humans, and other wildlife. our editorial process Russell McLendon Updated September 14, 2020 guillaume regrain / Getty Images Share Twitter Pinterest Email Animals Wildlife Pets Animal Rights Endangered Species Earth is a primate planet, thanks primarily to the 7.3 billion humans who inhabit and reshape its surface. But behind this conspicuous sea of people, the story of Earth's roughly 700 other primate species and subspecies is a lot less triumphant. More than half of those primates are now in grave danger of becoming extinct, warns a report by the world's top primatologists and conservationists. Our closest living relatives are being wiped out by large-scale habitat destruction — especially from the burning and clearing of tropical forests — as well as by hunting for food and the illegal wildlife trade. That's according to the latest list of Earth's 25 most endangered primates, which is updated every two years by scientists from the International Union for the Conservation of Nature (IUCN), the Bristol Zoological Society (BZS), the International Primatological Society (IPS) and Conservation International (CI). Here's a who's-who of the 25 most endangered primates on the planet according to the IUCN Primates in Peril report. 1 of 25 Bemanasy Mouse Lemur The Bemanasy mouse lemur (Microcebus manitatra) identified as a separate species in 2016 lives in a forest fragment in southeastern Madagascar that is under further threat from logging and slash and burn agriculture. Fewer than 50 individuals are thought to live in these forest fragments. At just over 10 and a half inches, they are one of the larger mouse lemurs. 2 of 25 Lake Alaotra Gentle Lemur The Lac Alaotra bamboo lemur lives only in papyrus reeds around Lac Alaotra, Madagascar. Jotaguru / Wikimedia Commons / CC BY 3.0 The critically endangered Lake Alaotra Gentle Lemur or Lac Alaotra Bamboo Lemur (Hapalemur alaotrensis) is called the bandro by locals. Estimates of the current population IUCN estimates the current population at 2,500 individuals. They are the only primate to live only in wetlands and call the shrinking Lake Alaotra marsh in Madagascar home. Conservation work has ended the hunting of the lemur for food. However, the agricultural use of the Lake Alaotra marshlands still hurts the population. 3 of 25 James’ Sportive Lemur Courtesy of Naina Rabemananjara The James Sportive Lemur (Lepilemur jamesorum) dwells in the Manombo Special Reserve region in southeastern Madagascar. Hunting with traps and cutting the trees and removing them from the holes they live in as well as deforestation led to their critically endangered status and an estimated population of around 1,386 total individuals. 4 of 25 Indri Dudarev Mikhail / Shutterstock The indri (Indri indri), also called the babakoto, found in the eastern rainforests of Madagascar, is the only lemur that sings. In addition to their singing abilities, they have a teddy bear appearance with short, dense fur, round ears, and small eyes. Long protected by taboos against hunting the species, the indri now faces extinction resulting from hunting as well as deforestation. According to the report, the estimated population size lies somewhere between 1,000 and 10,000 individuals. 5 of 25 Aye-Aye Homo Cosmicos / Shutterstock The aye-aye (Daubentonia madagascariensis) has the broadest range of any lemur. Their ability to consume a varied diet allows aye-ayes geographic flexibility. The aye-aye uses their long middle finger to tap on trees to find grubs. Poaching is the primary population threat to aye-ayes. Aye-ayes are endangered but reliable population estimates are unavailable due to their solitary nature and enormous individual territories. 6 of 25 Rondo Dwarf Galago Courtesy of Andrew Perkin The Rondo dwarf galago or Rondo bushbaby (Paragalago rondoensis) found in Tanzania is notable for being the smallest known galago and sports a bottlebrush tail. They have a distinctive "double-unit rolling call." Forest habitat loss is the primary threat to the Rondo bushbaby leading to their critically endangered status. The most recent recording of the species was four individuals in 2008. 7 of 25 Roloway Monkey guillaume regrain / Getty Images The endangered Roloway monkey called boapea by locals is (Cercopithecus roloway) found in the tropical forests of the Côte d’Ivoire and Ghana sports a long distinctive beard. Fewer than 2,000 individuals remain, and some parts of their former range have no remaining roloway monkeys. The bushmeat trade decimates their numbers each year, as 80% of the rural people of Ghana rely on bushmeat as their primary form of protein according to the report. 8 of 25 Kipunji Zina Deretsky, National Science Foundation / Public Domain The kipunji (Rungwecebus kipunji) first discovered in 2003, lives solely in the mountain habitats around Mt Rungwe in Tanzania. They have a particularly notable very loud low-pitched honk-bark. Kipunji serves as the flagship species for conservation work in the area. There have been significant strides in restoring the habitat though they are still in grave danger of dying out with only 1,117 individuals in 38 groups. 9 of 25 White-Thighed Colobus The range of the white-thighed colobus (Colobus vellerosus) is a quite fragmented distribution from the area between the Sassandra and Bandama rivers in Ivory Coast to Benin, possibly extending into southwestern Nigeria. Primarily black with white markings on thighs, face, and sporting an entirely white tail as adults an infant colobus is born with all-white fur darkens beginning around three months of age. Critically endangered, numbers are rapidly declining due to uncontrolled hunting, and the current population is estimated to be below 1200 monkeys. 10 of 25 Niger Delta Red Colobus Daniel Giraud Elliot, 1835-1915, modified by A. C. Tatarinov / Biodiversity Heritage Library The Niger Delta Red Colobus (Piliocolobus epieni) inhabits the forested marsh between the Forcados-Nikrogha Creek and the Sagbama-Osiama-Agboi Creek in Nigeria. Until 2008 they were considered a subspecies. The instability in the area has worsened habitat destruction and hunting pressures on the population which has dropped to an estimated few hundred individuals. They are considered critically endangered and face a real threat of extinction. 11 of 25 Tana River Red Colobus The Tana River in northern Kenya is home to this red colobus (Piliocolobus rufomitratus). Hydroelectric dam construction and the rapidly increasing human population in the area are responsible for the declining numbers of this species. It is listed as critically endangered with fewer than 1000 individuals remaining. 12 of 25 Western Chimpanzee Anup Shah / Getty Images Found in the rainforest and savannah woodland of Côte d’Ivoire, Ghana, Guinea-Bissau, Liberia, Mali, Republic of Guinea, Senegal, and Sierra Leone the Western Chimpanzee (Pan troglodytes verus) population declined by an estimated 80% between 1990 and 2014. At this rate, IUCN estimates by 2060, 99% of the remaining western chimpanzees will be gone. Illegal hunting leads as a significant threat to the population. The current population is estimated between 35,000 and 53,000 individuals, yet is critically endangered. 13 of 25 Javan Slow Loris irawansubingarphotography / Getty Images The Javan Slow Loris (Nycticebus javanicus) of Indonesia should have natural protection from the biggest threat to their species: capture for the illegal pet trade. They are the only venomous mammal. This fails to stop wildlife traders; they just pull the teeth before marketing them on social media where many viral videos are available. The Javan Slow Loris is critically endangered with uncertain population numbers. Conservation efforts do have numbers trending upward though. 14 of 25 Pig-Tailed Snub-Nose Langur Commercial logging has created the primary threat to the critically endangered pig-tailed snub-nose langur (Simias concolor) in the Mentawai Islands of Indonesia. The soil and tree damage makes the habitat incapable of supporting this species and other primates that call the forests home. Additionally, it makes for easier hunting of the pig-tailed snub-nosed langur whose meat is considered a delicacy. As a result, only 3,347 individuals are thought to remain. 15 of 25 Cat Ba Langur The Cat Ba Langur, also is known as the golden-headed langur (Trachypithecus poliocephalus), can only be found on Cat Ba Island in Vietnam. Once a dense population hunting led to a decimated population of only around 50 in 2000. Conservation efforts have led to a slow increase in the numbers, but it remains critically endangered. 16 of 25 Golden Langur Daniel J. Rao / Shutterstock The Golden Langur or Gee's golden langurs (Trachypithecus geei), native to India and Bhutan, were first discovered by E.P. Gee in 1953. The golden in their name is the golden orange fur that is only present during the breeding season. The rest of the year they are cream or dirty white in color. Major threats are power lines, road accidents, and dog attacks. With less than 12,000 individuals remaining in the wild, they are listed as endangered. 17 of 25 Purple-Faced Langur Jeroen84 / Wikimedia Commons / CC by-SA 3.0 The purple-faced langurs (Semnopithecus vetulus) of Sri Lanka face an uncertain future. Deforestation in Sri Lanka's dense Colombo region is the main reason why the western purple-faced langur is critically endangered. Ecotourism and programs for children seem to be the most effective protection for the species. 18 of 25 Gaoligong Hoolock Gibbon Sagar / Flickr / CC BY 2.0 The Gaoligong hoolock gibbon or Skywalker hoolock gibbon (Hoolock tianxing) has a population of fewer than 150 individuals and is listed as critically endangered. Habitat loss and hunting for bushmeat and the pet trade serve as the major threats to the population. 19 of 25 Tapanuli Orangutan Courtesy of Maxime Aliaga Once thought to be the southernmost population of Sumatran Orangutans, the critically endangered Tapanuli orangutan (Pongo tapanuliensis) was formally identified in 2017. Only around 760 individuals remain due to habitat loss from illegal logging and poaching for the pet trade. 20 of 25 Buffy-Tufted-Ear Marmoset Jack Hynes / Wikimedia Commons / CC BY-SA 3.0 The buffy-tufted-ear marmoset (Callithrix aurita) found in coastal Brazil and eats insects primarily. Invasive marmoset species, habitat loss and fragmentation, and an outbreak of yellow fever have decimated the population leaving fewer than 1,000 individuals of the critically endangered species. 21 of 25 Pied Tamarin belizar73 / Getty Images The pied tamarin (Saguinus bicolor) also known as the Brazilian bare-faced tamarin has a native range around Manaus the capital city of Amazonas in Brazil. City life doesn't agree with them where cats, dogs, power lines, and cars as well as capture for the pet trade threatens their population. They are critically endangered and numbers are thought to be declining though no reliable estimates of the population are available. 22 of 25 Ecuadorian White-Fronted Capuchin Rebecca Yale / Getty Images Only 1% of the original range of the Ecuadorian white-fronted capuchin (Cebus aequatorialis) remains in the Chocó and Tumbes eco-regions of Ecuador and Peru. These tree-dwelling monkeys are considered a pest by locals, particularly on corn, banana, cacao, and plantain plantations and crab hunting competition in mangrove regions. They are critically endangered with an unknown number of mature individuals. 23 of 25 Olalla Brothers’ Titi Monkey For 60 years after the first description of a single Olalla Brothers' Titi monkey (Plecturocebus olallae) there was no further information about the species. Finally, in 2002, they were spotted again. The small population lives in the Moxos Savannah in Bolivia and is under threat due to the burning of the savannah in order to grow cattle ranching pastures. Fewer than 2,000 individuals remain according to Primates in Peril and they are critically endangered. 24 of 25 Brown Howler Monkey RPFerreira / Getty Images Northern brown howler monkeys (Alouatta guariba ) serve as important seed dispersers due to their diet of fruit and leaves in the Atlantic forest of Brazil. Critically endangered, their habitat has shrunk dramatically due to coffee and sugar cultivation and cattle ranching. Additionally, yellow fever outbreaks have severely depleted their numbers and fewer than 250 mature animals are thought to have survived. The southern brown howler monkeys also have declining populations according to the report. 25 of 25 Central American Spider Monkey Mark Newman / Getty Images The Central American spider monkey, also known as Geoffroy's spider monkey (Ateles geoffroyi) has various populations of subspecies found in areas of Mexico, Guatemala, Nicaragua, Honduras, El Salvador, Costa Rica, Panama. They have a very limited diet and spend much of their time foraging. The cultivation of illegal drugs leads to 20-60% of the Central American spider monkey deaths each year states the IUCN report. Endangered with further decreasing numbers, fewer than 1,000 individuals remain.